BioDynamic Farming

The biodynamic movement originated from a group of eight lectures given by Rudolf Steiner in Poland in 1924. Rudolf Steiner was a Christian seer who originated the anthroposophical society. He is the originator of the Waldorf educational system and anthroposophical medicine. Farmers in the anthroposophical society asked him to address agricultural problems of their time. There were problems with the decline of soil fertility and farm viability even at this time, prior to the huge use of chemicals and poor farm management which has ensued since then. They were concerned about degeneration of seed strains in many cultivated plants. Crops could not be grown in the same fields for as many years as they had grown previously. There was an increase in animal disease, with sterility and foot-and-mouth disease amongst other problems. In the lectures, Steiner gave answers which nurtured sustainability of farms through health of the whole farm organism.  He requested farmers test his ideas rather than take them as gospel truth. Farmers have been using his methods ever since, getting wonderful results and adding to the biodynamic wealth of information.

Biodynamic farming is more than a body of information, it is a spiritual attitude towards all life. In biodynamic farming the farmer is considered a spiritual caretaker of the land. The farmer's job is to maintain a healthy organism through education, careful planning, spiritual guidance and thoughtful activity. She learns to become an intricate part of a larger organism. The farm becomes a holy place where daily activity takes place with reverence and love. All the beings on the farm depend on each other for their continued existence. An intricate web is formed. The farmer has direct experience of the rhythms of the seasons and intimate communication with the smallest of organisms unseen in the soil to the largest of organisms, such as the farm itself. There is a recognition of the interdependence of all the organisms which make up the farm.

A biodynamic farm strives to be a self reliant organism.  Manuring materials are produced on the farm via animal manures and green manuring. Composting is an integral part of the farm. Compost is enlivened with the use of biodynamic preparations from animal and plant substances which have undergone fermentation processes. Other biodynamic preparations are applied by spraying them directly on the soil or the plants themselves. These preparations support the life of the soil or support the plants ability to draw what it needs from the soil or from the sun and the rest of the cosmos. The biodynamic methods support the vitality of the farm organism as a whole. The emphasis is on quality of life and the health of the plants and animals. Whereas the main interest on most farms is on quantity, the main emphasis of a biodynamic farm is on the  increased  flavor, nutrition and vitality of the food as well as the enhanced life experience for all entities involved.

In biodynamic farming a plant can not be diseased by itself. If there is a  problem with a plant, there is something wrong with the environment. The environment of the plant is nourished so that it can sustain a healthy plant.

Biodynamic growth of healthy plants and animals supports the vitality of the human beings who consume these organisms.  Intake of these essential  life forces and the harmonious biodynamic lifestyle nourishes human beings, allowing them to live a rewarding life of equanimity.

Biodynamic preparations are used to rectify the chronic and symptomatic imbalances of our time. Small potentized amounts are used, similar to homeopathy. Over time the  preps in conjunction with respect for nature and good farming practices, bring the environment into harmony creating a healthy farm organism.

In Germany and Sweden experiments have compared vegetables grown with biodynamic methods and other modern day methods. The Biodynamic vegetables tend to have higher vitamin levels, higher  levels of true proteins, and longer storage times.  In European studies Biodynamic farms show increases in soil fertility over time.  There has been a lot of research comparing biodynamics with other farming systems. Unfortunately many of them are not in English. In 1995 The American Journal of Agriculture published a comparative study of Biodynamic farming and other farming practices from  English publications. This review was compiled by John Reganold, a crop and soil science researcher of the University of Washington (USA). It is called Soil Quality and Profitability of Bio-Dynamic and Conventional Farming Systems; In Review., Volume 10, number 1, 1995. This research review finds Biodynamic methods to have higher organic matter, microbial activity, enzyme activity, earthworm channels, earthworms and total nitrogen than the topsoil of chemically fertilized plots and control plots. Research has also shown higher nitrogen rates, organic matter, enzyme activity, microbial biomass and total nitrogen in biodynamic plots compared with organic plots.  Besides better soil found on biodynamic farms the studies showed that biodynamic farms had lower crop yields, but equal or greater net returns than their conventional counterparts. Lower crop yields were thought to possibly be due to choice of seed strains while increased returns were due to greater market worth of the Demeter (biodynamic certifying agency) certified products. The emphasis in bio-dynamic farming is on quality, not on quantity.  

PREPARATIONS EXPLAINED

Some of the preparations use cow, deer or elk organs as part of their processing.  Some people have asked if there are alternatives to using animal organs in these preparations. Perhaps, but I don't know of any. You may find it important to know that the deer and elk bladders in the Oregon Biodynamic group are harvested by a butcher who collects them for our group when someone brings an animal to him to butcher. The cow parts are harvested each year from one of the cows, which are butchered on a biodynamic group member's farm. We are using the parts of the animals no one generally makes use of. Animals are not dying specifically for this one purpose. Our group makes the preparations together. The preps are sufficient in number for our members as well as other people in our area who purchase them. The preparations are used in minute amounts just like homeopathic preparations.

#500

Horn manure - #500 is applied in the autumn and  spring as well as on transplants. 500 enhances root growth. It promotes root activity. It specifically stimulates soil micro-life and increases beneficial bacterial growth. It regulates calcium and nitrogen content. 500 helps release trace elements and stimulates germination of seeds. It is diluted in water, potentized, sprayed on the ground prior to planting, in seed beds and used as a root dip for transplants. It consists of cow manure packed into cow horns and buried around Michaelmas (September 29). It remains in the ground until spring. It is dug out between Easter and Ascension (Spring Solstice). In Oregon it is dug out as late as possible.

For one acre use one 5 gallon pale of water filled 2/3 full of water, add prep, stir for one hour. (see stirring directions) The 500 can be sprayed by dipping a whisk broom into the prep water and shaking the prep onto the soil. The prep must touch bare ground. 500 is best applied in the late afternoon or early evening. It should be applied on slightly moist ground and not in direct sun. It should not be applied  before a heavy rain.

#501

501 is used for above the ground growth, for the flowering and ripening processes. It enhances light metabolism of the plant. It stimulates photosynthesis and formation of chlorophyll. It influences color, aroma, flavor and keeping-quality of crops. 501 is made from very finely ground quartz. The moistened quartz is packed into a new fairly recently removed cow horn. This is buried in the ground from about mid June until the end of October or the beginning of November.

For one acre use one 5 gallon pale of water filled 2/3 full of water, add prep, stir for one hour. (see stirring directions) Put into a spraying apparatus used only for biodynamic preps. Spray in a very fine mist onto foliage or fruit, in the early morning, not immediately before rain.  This spray can burn tender new leaves if sprayed late in the morning on a bright day. Don't spray on transplants unless the root system is well developed and the plant is putting out vigorous new growth. This spray can cause lettuce or spinach to bolt immediately if they are close to bolting. Only spray early in their cycle.

COMPOST PREPS #502- #507

#502

502 assists plants in attracting trace elements in extremely dilute quantities for their best nutrition. 502 is made from Achillea millefolium (Yarrow blossoms) collected in June before St. John's Day. The flowers are picked prior to pollination or at least while they are fully vibrant, prior to making seeds.  They are used fresh or dried and reconstituted later. An empty stag or elk bladder is filled with these flowers. The bladder is hung in the air and sun until Michaelmas when it is buried. It is dug up between Easter and Ascension.

(Helps assimilation of minerals as a bio prep and as a medinial herb ingested by humans.)

#503

 503 stabilizes nitrogen within the compost and increases soil life so as to stimulate plant growth. 503 is made from reconstituted Matricaria recutita (German chamomile) flowers which are stuffed inside the intestine of a cow, bull, steer or  heifer. The sausages are buried at Michaelmas and dug up between Easter and Ascension.

#504

504 or Urtica spp. (Stinging nettles) stimulate soil health, providing plants with the individual nutritional components needed. It enlivens the soil.

504 is  made with Nettles. The whole top of the plant is collected in flower in June, before St. John's Day if possible. They are bundled together and placed into a hole lined with peat.

Nettles are also used as a fermented tea. This is sprayed on sick or stressed plants as a liquid manure.

#505

505 provides healing qualities to combat harmful plant diseases. 505 is made from Quercus spp. (Oak bark) around Michaelmas. The bark is gathered from a living tree. It can't be mossy or flaky. You can't go too deep into the red bark. The bark is ground, moistened and inserted into the brain cavity of a skull from a large domestic animal. Cows are usually used. All the holes are sealed with bones, wooden pegs or dowels. The skull is placed on the side of a small stream, or in a damp, marshy place where water will trickle through. The prep is removed in the spring.

#506

506 stimulates the relation between silica and potassium so silica can attract cosmic forces to the soil. 506 is made from unpollinated reconstituted Dandelion flowers. The flowers are wrapped in the fresh peritoneum of a bovine animal. It is buried at Michaelmas and dug up between Easter and Ascension.

#507

507 is used the evening before a frost is expected. 507 stimulates compost so the phosphorus content of the compost can be properly used by the plant.

507 is made from Valeriana officinalis (Valerian) flowers which are ground up immediately after  harvesting. The pulp  is squeezed through cheesecloth and the juice put into amber bottles with corks.

#508

508 is used to prevent fungal growth. It is helpful on seedlings to prevent damping off. 508 is made with Equisetum arvense (Horsetail). The sterile shoots are harvested in  May through June prior to the silica losing its organic bond and becoming crystallized. The plant is dried and used as a tea.

Bio-Dynamic Compost

Making Compost: 502-507 preps  One set of preps 502-507 is sufficient for a pile of 1-10 tons (one cubic yard of material). If you make a smaller compost pile, you still need to use the full set. The compost must sit on the ground. If you make layers, make them thin, about 2". Use coarse stalky material  on the bottom layer to trap pockets of air in the pile. Sprinkle small amounts of soil over each layer. The layers should consist of weeds or garden plants, leaves, animal manure and bedding, kitchen food and soil. These are used in alternate layers with soil spread between layers and on top. If limestone is added it should go in with the leaves. If adding rock phosphate, don't add it with the limestone.  To inoculate the pile with biodynamic preps, use the following method:  Use a broom handle or shovel handle to make 5 holes in the compost pile. They should be as far apart from each other as possible and the hole should reach half way to the ground or 1.5 feet from the top of the pile.  Each of the 5 preps get put into their own hole. Add preps 502, 503, 504, 505 and 506 into their separate holes. Cover the opening to the holes with the outer layer of compost and soil.  Take preparation 507 and dilute it in water (the water must be spring water, river water, rain water or if necessary tap water which has sat out for 2-3 days to let the chlorine evaporate), Use about 32 -64 oz of water in a quart jar or 1/2 gallon jar. Stir the mixture with a wooden stick or spoon. Stir for 15 minutes (See stirring directions). When the mixture is finished, make a 6th hole in the center of the pile and pour 50% of the mixture into this hole, sprinkle the rest of the mixture over the pile. 507 helps all the rest of the preps work together in a harmonious way. Once the pile is built, covered with earth or straw and inoculated with preps, simply leave it. It will be ready in 3-9 months depending on moisture and heat.

Stirring Preps

Use a stick which makes a good vortex in your pail of water. Also use a stick that is comfortable to hold. You need to use the stick to make a vortex all the way to the bottom of the pail. Tree prunings can be saved to use for these sticks. Get in a comfortable stirring position, start by making a vortex in one direction. As soon as it is well formed, quickly change directions creating a vortex in the opposite direction. The water will become chaotic, then a new vortex will form in the opposite direction. Once again reverse directions creating a vortex in the other direction. This alternation between a stable vortex and chaos between the two directions is very important.

Storage of Preps

Fill a cardboard or wooden box with peat and bury each prep so it is completely covered and surrounded by peat.  The box must have a lid on the top of it. Preps can be put into small glass jars with cork lids or earthenware containers. 500, 502-507 should be stored in the peat container. 501 should be stored in a glass jar with a cork cover or paper rubber banded over the top and left in the sunlight. Avoid storing the preps in metal or near electric wires or active machinery.

Timing is Everything

Biodynamic preps will enliven and enhance the cosmic rhythms which are already at play on any given day. This can be beneficial or detrimental. For this reason it is necessary to use them in conjunction with a guide of cosmic forces such as the Stella Natura. This is a publication created by Kimberton Hills. It is a biodynamic agricultural calendar. Sowing seeds, transplanting,  harvesting, thinning, pruning, weeding and other activities are all planned according to weather conditions, the plants needs and planetary forces or cosmic forces. This calendar gives us the play by play movements of the cosmos each day and break it down as to how it effects farming. It is well known by farmers that trees pruned in the full of the moon have more chance of losing large amounts of sap. It is also known the full moon is the best time for germination of seeds. These are some commonly known facts of farming due to the celestial influences of the moon and its effect upon earth's organisms. There are many other relationships between the celestial planets,  each other and how their physical movements effect farming on our planet. The more you learn these rhythms and use this knowledge in your farming, the better results you get. If you don't know much about the movement of the planets and their effects you will want to purchase a book such as Astrological Gardening to use in conjunction with the calendar.

If you want to know more about the herbs used in biodynamic farming, I wrote an article on the herbs which you can find at this link. Look for "Farm Data Blog Series"

Oregon BD Group: http://oregonbd.org

The Bio-Dynamic Farming & Gardening Association Inc

262-649-9212

http://www.biodynamics.com

National address for preparations and cow horns:

Josephine Porter Institute for Applied Biodynamics

PO Box 133

Woolvine, VA  24185-0133   phone: 540-930-2463

http://www.jpibiodynamics.org/

Suggested Reading:

1. Grasp The Nettle by Peter Proctor

2. BIODYNAMICS: Farming and Gardening in the 21st Century - a journal available from Josephine Porter Institute for Applied Bio-Dynamics

3. Agriculture by Rudolf Steiner

4. Herbal Renaissance by Steven Foster

5. Herbal Emissaries by Steven Foster

6. The Biodynamic Farm by Herbert Koepf

7. Bio-Dynamic Agriculture by Koepf, Pettersson, Schaumann

8. The Potential of Herbs as a Cash Crop by Richard Miller

9. Dirt, the Ecstatic Skin of the Earth by William Logan

10. The Earth manual - How to Work on Wild Land Without Taming It by Malcolm     Margolin

11. Astrological Gardening by Louise Riotte

12. Stella Natura by Kimberton Hills – purchase via Biodynamic Farming and Gardening Ass.

Biodyanimic Farming & Gardening

I get so many questions about biodynamic farming that I decided to share a couple articles that I wrote a few years back. I hope you enjoy them. They are located on my website resource page. There are two articles. One on biodynamic Farming called "Biodynamic Farming" and the second on the medicinal herbs used in biodynamic farming called "Herbs Used in Biodynamic Farming." To get to the resource page simply follow this link  http://herbaltransitions.com/herbalresources.html and then go to the "Farm Data Blog Series."

Garden Blog Series: How To Grow Carrots

Types of Carrots to Grow

Carrots are categorized into groups depending on shape and how deep they grow. I list a few common ones below.

Imperator: Thin, deep growing carrots of up to 10 inches

Danvers: These grow up to 7 inches long.  The tops are thicker and the flavor of the Danvers tends to be strong.

Nantes: These are sweet, round carrots that grow to around 6 inches long.

Chantenay: These grow around 5 to 6 inches. They are medium sized stocky roots which are more conical and have a good core and flesh color. Many consider these to be the tastiest of the carrots.

Purple, white and reddish varieties are also available on the market. I think the orange carrots are the best tasting ones though.

When to Grow

Carrots like cool weather, so you can sow as early in the spring as the soil warms up  (10C or 50F) and continue seeding them every six weeks until the fall. Usually, the last time you can sow them is about two weeks before the first expected frost date. You can start them earlier if you use a cold frame or row cover to cover them. Set up the row cover a few weeks before planting seed to warm up the soil.

Soil Preparation

Carrots grow best in a deep, loose soil that retains moisture yet is well drained. Carrots like loose, loamy, sandy, well weeded, well drained, soil. They grow great in sandy, soil with lots of organic matter. They do not like too much nitrogen in the soil so do not add manure or other high nitrogen fertilizer prior to planting. Even excess compost has caused my carrots to form multiple roots. The best soil pH is 6.5 - (5.5-6.8 will do.)

Sowing

You can sow your seeds after the last hard frost. Sow seeds directly in the ground and then thin. They can be planted about 3/8 inch into the soil The thinning distance is based on how big you want them to be when you harvest them. Will you harvest them when they are small or let them grow larger. Some folks like to have rows of carrots with some space between the rows. Other people like to grow them in large blocks quite close to each other. As long as you have good soil either way works fine. Give them enough room so they can get as big as you want at harvest time and don’t forget to leave room for you to get your fingers around them while pulling them out. This means you should usually thin them to about 3-4 inches between each one usually. If you have them overcrowded they will twist around each other from lack of room. They will taste good but look odd.

 Generally carrots are seeded and not transplanted. You can transplant them but transplanted carrots tend to fork.

Soil temp of 10c (50F) is good for germination. At this temp it usually takes 10 days for the seed to germinate.

Plant every 6 weeks or so for continual carrot harvest.

Watering

Light watering often promotes shallow root development and can increase the crop's susceptibility to hot weather and drought stress. On most soils, watering once a week is sufficient. Very sandy soils may require more frequent watering.

Not enough water creates tough roots with feeder roots extending off them. Too much water can cause the root to split all along its length. This usually happens close to maturity.

What Not To Do

Do not plant in heavy, clay soils with lots of rocks.  Do not plant in compacted soil. Do not put fresh manure in soil where carrots will grow or use other types of nitrogen fertilizer prior to putting carrot seed in the soil or you will get forked carrots rather than straight carrots. Even too much compost has caused this problem for me.

Minerals

They require moderate to high levels of phosphorus and potassium. Phosphorus can be added as rock phosphate and potassium can be added as ashes from your wood stove if you have one. Don't over ash though just because you have a lot of ashes. If the soil is too acidic lime can also be added. Carrots grow poorly in soil with high amounts of sodium. It is always helpful to get a mineral analysis of the soil in your garden before adding minerals.

Why My Carrots Look Odd

Forked roots: May be due to rocky or stoney soil or heavy, lumpy soil. Transplanting of long-rooted vegetables will also lead to forked roots. Too much nitrogen will cause the carrots to become forked too. 

Hairy, Tough Roots: If carrots don’t have enough water, the main root will form small feeder roots to soak up more moisture. They also form extra tissue to help carry the water. This extra tissue makes them tough. 

Small hairs all over the root: This is often due to an excess of fertilizer.

Split Carrots: Carrots can split along their entire length when there is too much moisture. This usually happens close to maturity.

Green Shoulders: This is due to the top of the carrot sticking out of the ground. It turns green when it is exposed to the sun. They can be exposed due to heavy rains washing soil away or the carrot pushing itself upward out of the soil.  The green part is not dangerous but will taste bitter so cut it off. 

Twisted Carrots: They did not have enough room and the roost twisted around each other. Give them more space next time. They may have run into rocks too.

Leaves Turn Yellow & Die: Aster Yellow Disease – A bacterial disease that causes young inner leaves of carrots to yellow and later form dwarfed leaf clusters. Slightly affected plants may still be edible. The roots usually bulge at the crown, are stunted and have many hairy secondary roots. Leafhopper insects spread this disease, so the best control is prevention of them. Cover vulnerable carrot plants with row cover right after sowing the seed. Certain carrot varieties, such as Scarlet Nantes and Royal Chantenay, are somewhat resistant to aster yellows.

Harvest

They can be harvested about 50-90 days after planting depending on how big you want them to be. Carrots are usually harvested when the roots are ¾ inches in diameter at the upper end, but you can harvest them any time they reach a usable size. If the soil is nice and loose you may be able to pull them out easily with your hands. If not,  loosen the soil around the carrot first, be careful not to break the root while pulling it.

Storage After Harvest

Wash them, let the moisture dry off so they are not wet, but quickly get them in the bottom of your refrigerator in a plastic bag. If you store them somewhere else, make sure they are close to 32 degrees farenheit and keep the humidity high.  You can also dig outdoor pits to store through the winter or buckets filled with sand that are left in root cellars, basements or I even store such buckets in my barn in the winter. I only wash them if I am storing them in my refrigerator. I don’t wash them if storing them in a bucket of sand or outdoor pit.

Disease & Pests

Carrot Rust Fly

Carrot Rust Fly (CRF) - (Psila rosae) is the main pest that I have had to deal with. I don’t have any other problems growing carrots as a general rule. The largest carrot growing region in the United States is in Washington State and CRF is the number one problem they deal with there. A couple other pests of carrots are the Aster Leafhopper and the Carrot Weevil. Since CRF is a large problem here, I will tell you a lot about it.

Besides carrots, the CRF also attacks other garden plants including parsnips, celery, celeriac, and parsley. The CRF larva(maggots) damage plants by eating small roots and by tunneling in larger roots. A rust-colored material develops in the tunnels, giving the insect its name. The infected plants may become yellow, stunted, and die. Usually the plant tops continue to look healthy. The larva often continue to feed in stored carrots. Disease organisms may enter the feeding tunnels and cause the root to rot.

The CRF flies into the garden or field of carrots to lay eggs at the base of the carrot.  Then they leave the area. Three – ten days later the eggs hatch into larva and move into the soil and feed on the carrot. They migrate down through the soil along the carrot root and penetrate the carrot as they feed. Larva feeding results in tunnels along the surface of the carrot and rust colored frass. The larva will eventually pupate in the soil. When the adult fly emerges from the pupal case, it flies back to the edge of the garden or field.

You will not know you have CRF damage until you lift a carrot at harvest time. Then you will see the dark colored tunnels in the carrot. If you have a really bad infestation you might notice the carrot leaves turning a orange or rusty color followed by a yellow color.

What Do They Look Like & When are They a Problem

The adult fly is 1/5 inch (5-6 mm) long and has a dark, shiny body with straw-yellow legs and head and large red eyes. In the Pacific NW the CRF lays eggs in May and June on the soil surface around the plants. The eggs hatch in a 3-10 days and the larva feed on and in the roots. The maggots are yellowish white and reach about 1/3 inch (8 mm) in length. They feed about a month and then change into brown pupa about 1/5 inch (5 mm) long. The pupa stay in the soil near the roots until August when the adult flies emerge. The adult carrot rust fly is a slender, shiny, black fly, about 6 mm long, with a small but characteristic reddish head and long yellow legs. The new flies lay more eggs which change to larva. This group causes plant damage into the fall. Some flies may develop in the fall. These insects spend the winter as pupa in the soil or as larva in the roots.  Larva from the August-September generation cause the greatest damage. Damage generally increases the longer the carrots are left in the ground.

What Conditions Favor CRF

• A previous history of rust fly infestations.

• Consecutive annual plantings of carrots in the same spot.

• Fields surrounded by brush and woods.

• Soils with high organic matter content.

• Lots of CRF weed hosts in area.

Management of Carrot Rust Fly

Monitoring

Carrot rust fly adults can be monitored with orange/yellow sticky traps placed in the carrot field or in nearby trees where the adults rest.

Identify and Remove weed hosts

Other Apiaceae or carrot family plants can host the flies. They include common garden veggies such as parsnips, celery, celeriac, and parsley. They also include herbs or weeds such as dill, coriander, wild carrot, lovage, fennel, parsley and all the other Apiaceae family members.

Plant Late

Avoid early-season egg laying by planting after early adults have emerged and dispersed. Mid to late June is a good time in my area to plant and avoid the flies. However if you have neighbors with carrots or other alternate plant hosts are in your garden this won’t work.

CRF Are Attracted to the Scent of the Carrots

The CRF is attracted to a chemical that the carrots produce when they are under environmental stress. Even weeding the carrots and moving the leaves around may release more of this scent and attract the flies. So weed when there is no wind so the scent does not travel far or weed in the evening when the sun is going down as the fly takes air only in bright sunlight. Pulling the carrots in the evening is also helpful for this same reason.

Confuse the Flies with Strong Smelling Herbs

Some folks have good results putting strong smelling dry herbs around the base of the carrots such as pennyroyal, rosemary, sage and wormwood. Since they lay eggs at the base of the carrots covering the soil with a strong smelling herb will both confuse them and cover the soil where they would usually lay eggs. Some people also plant between row crops of strong smelling herbs.

Cover Crops Planted Between Carrot Rows Can Also Confuse them

Growing the carrots with cover crops between them has been an effective solution to keep the CRF from finding them. Some cover crops that have been used are Crimson Clover, Medic, Subterranean Clover, Vetch and White Clover.  Additionally, they help enrich the soil. These crops enhance the soil and provide cover for beneficial insects. It is thought that they help hide the smell of the carrots and confuse the flies.

Row Crop Covers Can Be a Physical Barrier to the Flies

Covering the carrots with a floating row cover works for garden growers but is hard for people who have large fields of carrots. Seal them well at the soil line. Be sure you do not have maggots or pupae in the soil where you place the row cover though. Never grow carrots on a soil area that was infested with rust fly the previous year.  Carrots and other Apiaceae family members should never be planted in the same area as the prior year.

Raising the Carrots more than 18 inches off the Ground

Since CRF usually flies no more than 18 inches above the ground, some folks have grown them in raised beds above this height. Here is a video of one such method.

Rotate Crop
They are weak flyers, they tend to stay localized. They are thought to travel less than 1000 yards in search of egg laying sites. They are atracted to host crops and fly upwind towards the smell. Isolation of your crop from last years field or garden area can reduce risk. Not every gardener has the space to move their crop that far though. This works better on a farm.

Clean Up
Discarded piles of overwintered carrots or parsnips can be a source of flies and should be removed. Leaving your carrots   or parsnips in the soil over the winter is also a place they can hibernate until spring. 

Mulch Them or Apply Ashes
Mulching with grass cuttings/straw or applying diatomaceous earth or wood stove ashes around them can make it harder for the female flies to find a good egg laying site. If you mulch be aware that slugs and snails like to live in mulched areas.

Beating the Carrot Root Fly

http://www.youtube.com/watch?v=ORB1-EtLIjM

Birds

Birds and chickens serve as excellent biological controls in fallow ground where pupae are suspected. If you can put your chickens in the garden without causing damage (Chickens scratch up bugs from the ground, so if you don't want them damaging roots, be careful where you put them.) they will help clean up many bugs.

When You Have the Fly in Your Carrots Harvest Early and Don’t Provide them With A Place to Eat

Early fall harvesting and storage of carrots in pits and root cellars rather than in the ground help minimize fall infestations caused by late second or early third generation larva. 

Get rid of these carrots quickly. Do not store buggy carrots in the ground through the winter. If they are still worth saving, harvest them and put them in cold storage where larva can’t get back into the soil. The larva still in the soil is starved to death as long as there are no other carrot family plants around. Carrots with worms can still feed your animals.  I give them to my goats. You may have an animal who might enjoy them too. I feed all wormy garden produce to farm animals to remove the worms from my farm.

What Non-Organic Folks Do (Don’t do this at home kids!)
Non-organic folks use insecticides even though they have limited effectiveness against CRF. This is due to the fact that the adult rust fly spends most of its time on the periphery of your garden or field. They fly into the garden or field to lay eggs and then leave the area. After the larva hatch they move into the soil and feed on the carrot. It eventually will pupate in the soil. When the adult fly emerges from the pupal case, it flies back to the edge of the garden or field. Many types of pyrethroids and organophosphates have been tested to kill or control CRF. It has been found that the pyrethroids do not appear effective against eggs and larvae , but do decrease adult populations with continual broadcast spraying. This also kills all the beneficial insects and even the non-organic folks usually realize this type of constant over-spraying is hazardous to the end user of the carrot. Some organophosphates have been effective against the larval stage and the recommended pesticide for control of CRF in the Pacific NW is to use Diazinon at the time of planting the seed as a seed furrow drench. I don’t know about you but I don’t want to eat any carrots that had their seed drenched in Diazinon. There is a good chance if you eat non-organic market carrots that your carrot was grown in a Diazinon drenched garden. So if you buy carrots, only buy organic ones.

Carrot Weevil

The carrot weevil adult is a dark-brown snout beetle about 6 mm long.  It over-winters in plant debris in and about carrot plantings that were infested the previous year.

In the spring, adults become active and mate after a few warm days. They are capable of laying eggs by mid- to late May. However, they do not attack the new crop of carrots until the first true leaf stage. Adult females chew small cavities in the crown of the carrots and deposit two to three eggs in each cavity. They seal the cavity with a black exudate. Eggs hatch after one to two weeks and the young larvae tunnel down into the root or leave the stalk and enter the roots from the soil. Some young plants may wilt and die as the slender root is tunnelled by the developing larva. The damage is not otherwise conspicuous until the larva are nearly mature.

After feeding for at least three weeks, larvae leave the carrot and pupate in the soil. After one to two weeks, adults emerge. If warm weather or an early carrot crop has permitted the adults to mature early enough in the summer, some second-generation eggs and larvae may occur.  In warm areas second-generation injury is more common.

Management of Carrot Weevil

Monitoring the activity of carrot weevil adults is an effective means of determining the level of weevils. Wooden-plate or carrot-root sections placed in the soil can be used to monitor adult activity, starting at the time of seeding. 

Carrot weevil adults rarely fly and therefore the insect does not spread rapidly. Its presence in a particular location should be evident for a season or two before it builds up to serious levels. Development of a serious infestation can be delayed by not planting carrots on or adjacent to sites that were infested the preceding year.