Organic Production of Horticultural Crops

Producing Organic Horticultural Crops

Organic production involves a combination of management techniques to maintain soil quality and fertility while controlling weeds, pests and diseases. Crop rotation plays a big role in achieving these goals.

In order for horticultural crops to be considered "organic," they must meet the Organic Products Regulations and Canadian Organic Standards. These are uniform standards that all organic agricultural products sold in Canada must comply with.

There are several accredited organic certification organizations in Saskatchewan. Their standards vary slightly, partly due to different interpretations of "restricted use" products. Organic producers must pay attention to the requirements of the agency they choose to certify their production.

Consumers often interpret "certified organic" produce as merely pesticide free, but this is not always the case. Approved organic pesticides may have been used in some cases. Organic crops must always be produced according to accepted guidelines of the organic standard being followed, including soil management practices.

Vegetable crops

While home gardeners can grow the majority of vegetables "organically," the list of crops suitable for organic production is limited for commercial production. Markets for organic produce have increased in the last decade, but some vegetables are considered too high risk for commercial organic production, particularly cabbage and related vegetables. Pest control for these crops is very difficult and is compounded if the crops are located in regions where canola and mustard are being grown. If they are to be attempted, these crops need to be well isolated from crops that share the same pests.

Carrots

Carrots are considered to be one of the easiest crops to grow organically due to the limited number of pests. However, they should not be planted near alfalfa or other hay and winter cereals, due to the incidence of leafhoppers in these crops, which can spread aster yellows disease to carrots. The disease causes stunting or discoloration of carrot foliage, and extremely hairy roots that are unmarketable. As carrots are slow to germinate and are poor weed competitors when young, weed control is generally the greatest challenge in growing carrots.

Pumpkins and Squash

Pumpkins and the various types of summer and winter squash, including zucchini, are also potential crops for organic production. They are not prone to many insect pests or diseases in Saskatchewan. Selecting early maturing winter squash is important due to the short growing season in Saskatchewan.

Potatoes

While not highly recommended for organic production in Saskatchewan, a few producers have successfully grown potatoes organically. Disease control, particularly for blight, is of major concern. Insects such as Colorado potato beetles, flea beetles and wireworms can also be major problems. This crop is best grown well isolated from other potato fields and with long rotations. Careful cultivar selection may assist in disease control.

Sweet Corn

Sweet corn is a popular item at farmers' markets, roadside stands, supermarkets and market gardens. One of the greatest challenges in growing sweet corn is providing it with sufficient nitrogen to meet its very high requirements. Growers also need to look for untreated seed. Corn seed maggot, corn earworm and European corn borer are potential pests.

Onions

Organic production of onions is very risky, due to the high likelihood the crop will be infested with onion maggots. Without the use of conventional pesticides, it may be very difficult to produce a profitable, marketable crop. If onions are to be planted, it is suggested to plant the crop about 1.6 km (1 mile) from previous onion cropland. Although they prefer onions, onion maggots can also infest garlic, leeks, chives and shallots. Onion thrips are another common problem. They will migrate from alfalfa and cereal crops at harvest time. Heavy irrigation is known to reduce thrips populations.

Cole Crops (Cabbage Family)

Vegetables in this group are not recommended for organic production in Saskatchewan, due to the high incidence of pests. This family includes: cabbage, cauliflower, broccoli, Brussels sprouts, kohlrabi, kale, radish, rutabaga and turnip. They are very prone to imported cabbageworm, diamondback moth larvae, root maggots, red turnip beetle, flea beetles, cabbage thrips and wireworms. The incidence will be higher in regions where canola and mustard crops are being grown. Of the group, rutabagas and turnips are particularly difficult to protect organically from root maggots.

Other Vegetables

Many other vegetables are somewhat intermediate in their ease of cultivation by organic methods. Some of them are listed here, along with potential problems.

• Asparagus - this perennial crop is not widely grown in Saskatchewan. The early spears can be a target for overwintering onion thrips. Asparagus beetles, exclusive to this crop, can also feed on spears and make them unmarketable. Crown and root rot may be managed to some extent by cultural practices.
• Beans and Peas - untreated seed must be used, making them more prone to seed and/or root rot. Powdery mildew is a common problem in peas, particularly late in the season.
• Beets - if marketed with tops attached, beet leafminer control will be necessary. Row covers may be considered. Adjacent weeds such as lamb's-quarters are also hosts for leafminer. Rotations are helpful in minimizing problems with leaf and root diseases. Swiss chard and spinach share some of the same pests and diseases.
• Celery - this crop needs an ample water supply at all times to keep growth succulent. Water stress will cause tough, strong flavoured stems. Tarnished plant bug can cause serious damage to this crop; thus it should not be grown near alfalfa fields.
• Cucumbers - are generally easy to grow, but need a consistent water supply, especially when fruit is developing. Cucumber beetles can spread bacterial wilt disease. Transplanting and the use of row covers early in the season will provide earlier harvests.
• Lettuce - leaf lettuce is the easiest to produce but highly perishable when harvested. Romaine and head lettuce are later maturing. Lettuce should be marketed as soon as possible after harvest. Tipburn resistant varieties should be grown. Lettuce is prone to various diseases including Sclerotinia (white mould). Using raised beds and rotating fields with grain crops may be helpful. Aster yellows disease, spread by leafhoppers, may also be a potential problem, but the incidence is quite variable from year to year.
• Melons - both muskmelon (often called cantaloupe) and watermelon are long-season crops that need warm weather to produce well. Production in tunnels, on plastic mulch or season-extending greenhouse-type structures has given earlier yields. These crops are best grown on sandy land that warms up easily.
• Peppers - by both organic and conventional methods, unless grown in a protected structure, peppers are somewhat of a gamble in Saskatchewan. They prefer a warm, long growing season, although excessively hot summer temperatures can cause flower bud drop.
• Spinach - beet leafminers are a major problem in this crop, so it may not be profitable unless it can be grown in isolation or under row covers.
• Tomatoes - are susceptible to early and late blight, cutworms, and sometimes to Colorado potato beetles. In Saskatchewan, early maturing and cold-tolerant cultivars are required unless the plants are to be grown in greenhouses.

Herb Production

Culinary Herbs

A wide range of herbs can be grown outdoors or in greenhouses. Some herbs such as sweet basil and rosemary are very adaptable to greenhouse production. Organic garlic is in demand in some areas, but production may not be practical on a large scale because garlic must be kept weed free and can be affected by some of the same pests as onions. Growers may find the garlic seed market to be more lucrative than the culinary market.

Most culinary herb production needs to take place near urban centres where farmers' markets or restaurants can be supplied, unless the grower plans to dry and package the herbs for later use. Other value-added products are also possible, including herbal tea mixtures, flavoured vinegars and oils, as well as packaged seeds.

Medicinal Herbs

The vast majority of medicinal herbs grown in Canada are produced organically. Aside from spearmint, which has had only regional production in Saskatchewan, and those herbs which are also regarded as spice or oil crops (such as borage and dill), only Echinacea has been the major herb crop to date. However, markets for medicinal herbs are very volatile and growers need to use caution before planting any medicinal herbs on a large scale. As with vegetables, medicinal herbs are mostly grown as row crops. Pest and disease problems are known for some and the incidence could increase if acreages become significant.

Other medicinal herbs that have been produced (mostly organically) in Saskatchewan include astragalus, burdock, calendula, catnip, chamomile, ellacampane, feverfew, licorice, marshmallow, milk thistle, motherwort, mullein, red clover, skullcap, St. John's wort, valerian and yarrow.

Even some weeds, such as stinging nettle and dandelion, may be marketable. Aster-yellows and Sclerotinia diseases have occasionally been serious problems in some of these crops.

Herb crops for cosmetic uses are also gaining prominence. Willow herb (fireweed) is one example. Much of it is gathered from the wild, rather than being cultivated.

Fruit Crops

The list of suitable fruit crops for organic production in Saskatchewan is rather limited.

• Sea buckthorn - this fruit does not have a fresh market, but has been marketed in processed form. It is often regarded as a nutraceutical product because of its high nutritional value. Harvesting and marketing are the main challenges with this crop. Suckering can also be a problem in established plantations. Development of thornless cultivars is deemed desirable for the prairie region.
• Sour cherries - the hardy cultivars developed by the University of Saskatchewan are showing much promise, and it should be possible to grow them organically. In time, pest control may be more difficult. Carmine Jewel was the first sour cherry released by the University of Saskatchewan in 1999. "Romance" series including "Juliet," "Crimson Passion," "Valentine," "Romeo" and "Cupid" were released in 2004. Various fruit flies, and possibly caterpillars, may need to be controlled on cherries.
• Haskap - an edible blue honeysuckle, Lonicera coerulea, is a relatively new fruit that shows promise. The haskap has proved to be an easy-care shrub that has had use as a hardy ornamental shrub. haskap is thought to be immune to the honeysuckle aphid, which often is very damaging to Tatarian types. A number of new haskap varieties have been released from the University of Saskatchewan fruit program that show considerable promise for organic production
• Apples - have been grown organically in various parts of Canada and the USA. They are not without challenges. In recent years, apple maggot has become established in Saskatchewan and will have an impact on whether organic production is feasible here. Apple seed chalcid and fireblight can also cause problems. Apples have not been a traditional commercial crop on the prairies, but newer cultivars, with improved quality and hardiness, are making commercial ventures less risky. At present, organic production here should be considered only on a trial basis. Plums should also be considered in this category.
• Raspberries - organic production may be somewhat difficult because of various pest problems, including raspberry crown borer, raspberry sawfly, raspberry fruit worm and spider mites.
• Strawberries - pest control for numerous insects will likely be difficult for organic producers. These include several plant bugs and strawberry root weevils. Diseases such as botrytis, causing fruit rot, can also be of concern.
• Saskatoon berries - this crop is a very poor candidate for organic production on the prairies. Pest control for Saskatoon berries is vital, and the lack of organic pesticides for control of pests such as saskatoon bud moth and woolly elm aphids makes this crop a very risky venture except by conventional means. At best, production should be limited to very small scale operations.
• Other fruit - black currants are gaining popularity and require some pest control measures. It may be possible to use red currants or gooseberries as lure crops so that the black currants will have a reduced incidence of pests such as currant fruit fly. Further research may be required to determine the effectiveness of this control method.

Other fruits such as high-bush cranberry and hardy grapes might be possible where a market can be established. Rhubarb, while technically a vegetable, is often considered with fruit crops. It usually has minimal pests and might be considered for organic production.