There are many reasons to avoid or limit the use of synthetic fertilizers and pesticides around the home, not the least of which is concern over health. Direct, unnecessary exposure to synthetic pesticides can impact yours and your family’s health, especially your pets and children. Other reasons include protecting biodiversity, water and air. And so, many gardeners are making the choice to eliminate them entirely and go organic, using ‘green’ alternatives instead.
For gardeners just starting down this path, it can be a challenge since we’ve come to rely on synthetic, conventional garden products to fertilize and control pests. Organic production takes an integrated approach using a combination of cultural, biological and mechanical practices.
So what does it mean to ‘go organic’? To start, you need to re-educate yourself. For a list of allowable organic products, check out the Canadian Organic Standards (www.cog.ca). In the USA, the US Department of Agriculture-National Organic Program (www.ams.usda.gov/nop) maintains a similar list. In addition, there are several books (including Sara Williams and Hugh Skinner’s recent Gardening Naturally: A Chemical-free Handbook for the Prairies), magazines and blogs on the topic to help the new organic gardener.
There is still a need to fertilize. Otherwise, you’re simply robbing the soil every time you harvest produce or mow the yard and remove the clippings, leading to lower vigour and productivity. Some organic soil amendments include organic sources of compost (no grass clippings from lawns fertilized with synthetic fertilizers or treated with weed killer), rotted manure (from organically raised livestock only), alfalfa pellets, kelp and peat (no synthetic wetting agents). Growing legumes and green manure crops will add nitrogen to the soil. And all of these add organic matter to the soil, enhancing the microbial activity and nutrient cycling; improving water and nutrient holding capacity and increasing tilth.
The seed you sow must also be organically produced. Pelleted seed to improve handling of small seeds (e.g. carrot) is allowed, but fungicide- and insecticide-treated seed is not. GMO seed is likewise not allowed in organic production.
Pulling, hoeing and tilling are your main weed control methods. But there’s also horticultural vinegar (strong acetic vinegar) for non-selective vegetation control; mulch (e.g. newspaper without glossy or coloured inks; wood chips; straw; plastic film [allowed under USDA regulations], etc.) for smothering weeds seeds and seedlings, and corn gluten for dandelion seedling control (also a nitrogen source). [Note: organic mulches (compost, peat, wood chips) have the added benefit of conserving soil moisture and moderating soil temperatures.]
At the early stages of insect pest infestation, squishing is the most practical option. Insecticidal soaps, diatomaceous earth, horticultural / dormant oil and some botanical preparations (e.g. pyrethrum extracts but not synthetic pyrethroids) can be used to control larger infestations (read label and follow all safety precautions). These products are broad-spectrum killers, so spray in a targeted manner and avoid spraying when bees and other pollinators are about. Bt (Bacillus thuringiensis, various strains) preparations control caterpillars (e.g. imported cabbage worm). Often overlooked is the tireless effort of pests’ many natural enemies. Depending on the species, a single ladybird beetle can consume over 100 aphids per day. A great source of information on prairie insect pests and their natural enemies is the new Agriculture and Agri-Food Canada’s free Field Crop and Forage Pests and their Natural Enemies field guide by Hugh Philip (http://publications.gc.ca/collections/collection_2015/aac-aafc/A59-23-2015-eng.pdf).
Cultural pest control methods include crop rotation, using crop covers (large fabric covers), plant early or late to avoid the damaging stages of a pest’s lifecycle and growing non-GMO disease and insect resistant varieties. You can also grow a trap crop as a perimeter to concentrate the pest to one area, to keep them from the desired crop and to make control easier.
Finally, there’s acceptance. Accept that you will have some less than perfect fruit and veggies. Accept that production may be less than if you used synthetic fertilizers and pest control products. Accept complete pest control is neither practical nor desirable if you want to maintain natural enemy populations.
This column is provided courtesy of the Saskatchewan Perennial Society (www.saskperennial.ca; email@example.com; NEW www.facebook.com/saskperennial). Check out our Bulletin Board or Calendar for upcoming garden information sessions, workshops and tours. Visit our booth at Gardenscape, April 8 – 10.