Next to people cooperating to maintain the garden, soil development is the most important ingredient for a sustainable garden. Focus on soil health first and food crops second.
The first step to healthy soil is ensuring there are no toxic contaminants. Your City of Calgary Parks Community Strategist staff member can check to see if Phase I environmental assessments have been done in the vicinity of the garden. If the assessments do not indicate contamination concerns, approval will be granted to build garden beds without a sealed, leak-proof bed liner. This means that roots could reach into the soil below the raised bed in order to grow.
Use a reputable soil provider and have a conversation with them about how they assure that the soil they sell is not contaminated by pesticides, heavy metals or petrocarbons. Before you purchase soil for gardens ask the soil provider for the composition of the soil they are selling. Good soil will have as much as 25 percent compost and will hold together loosely if you clasp it once in your hand. Avoid soil that is powdery because it probably has less than 10 percent of organic matter. Ideal growing conditions for vegetables in a raised garden bed include about 50% compost proportion in the soil.
“At all times during the garden site development, any signs of soil contamination such as odours, discolouration, foreign objects etc. should be reported immediately to the Parks Community Strategist and the contamination will be investigated.
Us only potable water to irrigate plants intended for human consumption. Loam or soil amendments brought on site to supplement in-ground planting beds must come from a clean source. Use loan from a clean source to fill above-ground beds. Above-ground beds should have adequate drainage, and be deep enough to fully accommodate the root zone of edible plants. In-ground planting is restricted to fruit bearing trees and woody fruit-bearing shrubs. All vegetables, herbs and soft fruit must be confined to above-ground beds.”
Source: City of Calgary Parks
Tips for Ensuring Healthy Soil
Most leafy crops will grow in six inches of compost-enriched soil, while most root crops require around 18 inches of soil.
New and established community gardens have access to a limited amount of municipal compost on a first-come first-serve basis. Contact City of Calgary Parks and ask for the Program Advisor for Parks, Environmental and Educational Initiatives.
How it happens: The Parks representative will get in touch with the Superintendent of the East Calgary Compost Facility and Waste Management Facility Disposal and Processing Services of Waste and Recycling Services.
Community garden requests for City of Calgary compost are handled on a first come first served basis. Community gardeners are required to pick up the compost themselves earlier in the workday before the landfill closes at 5 pm.
So, how do you ensure all of that healthy soil? We’ve compiled a few tips:
Get to know your soil. Most soil in Calgary is alkaline with a pH 7.5 – 8. Home testing kits for soil pH can be purchased from most garden centers.
- Avoid tilling the soil in order to leave microscopic soil structures undisturbed.
- Use crop rotation and change the layout of gardens to balance out the nutrients removed and replaced by plants.
- Sow field peas early in spring to add nitrogen to the soil. Then turn them under into the soil or plant around them.
- Sow cover crops in shared garden beds during the fall in order to add nutrients for next year’s growing season. Cover crops add soil nitrogen, lessen soil erosion, improve soil quality and reduce opportunities for weeds to grow.
- Add compost to garden beds in the fall for maximum fertility the following spring.
- Educate as many of the garden members as possible in how to cook up a great batch of compost.
- You can warm up soil in the spring in order to give plants a good start. Clear away mulch so that the soil is exposed. Lay black plastic over the soil and secure the edges of the plastic to hold it in place. After a few weeks remove the plastic sheeting and place seedlings into the warmed up soil.
- If you are going to use animal manures in the soil, make absolutely sure they are more than 2 years old and are from herbivores (such as chicken, horse, sheep, cow) and not from carnivores because of the health risks when growing food crops with children active in the garden.
- Wear gardening gloves and shoes at all times when handling soil. The tetanus bacteria lives in soil naturally and if you have a cut anywhere on your skin it can enter the cut and make you ill. Symptoms of tetanus infection include feeling unwell, difficulty swallowing, and muscle stiffness. Keep your tetanus vaccinations up to date and seek medical help if you get a deep cut while gardening.
Make Some Earth!
- Mix 1 part shredded fruit / vegetable peelings + 4 parts dried brown leaves.
- Add water & stir twice a week.
- Serves up soil in 12 weeks.
Occasionally a garden will have a high water table or contaminated land. In these instances, the raised garden beds must be very effectively sealed to ensure plant roots only grow in soil that is brought into the garden and never touch the materials below. In a sense, this is a form of container gardening. Every container must have a way of draining out moisture but not taking in water or nutrients from the surrounding land.