How to Grow Vegetables in Tires

The Environmental Protection Agency (EPA), in 2003, estimated that about 290 million tires were disposed of as scrap -- about 9.3 percent of those ending in landfills. Because no gardener ever has sufficient containers in the garden, it makes sense to use tires for growing vegetables thereby solving two problems simultaneously.

Tires may contain nasty substances such as motor oil, gasoline or automotive cleaners that you do not want in your vegetable garden. Wash each tire inside and out with hot, soapy water -- and an environmentally-safe degreaser if necessary -- then rinse well, before using in the garden.

If you live where summers arrive later than is ideal for many heat-loving vegetables, setting young seedlings out in a cold frame or mini-greenhouse is a good way to get a jump start on space-hogging, heat-loving crops such as vining squashes (_Cucurbita spp_.). In areas with short growing seasons, tires converted to mini-greenhouses can take small-space crops like bush-style garden tomatoes (Solanum lycopersicum) straight through from seedling to harvest.

Clean tires -- large passenger or light truck size

Shovel or trowel

Soil amendments, as needed

Seedling plants

Water container

Clear sheet plastic or glass pane large enough to cover the tire

Use your chosen tire as a template to draw a circle, then dig a hole approximately two or three inches deep within that spot. Turn the soil well, at the same time incorporating any soil amendments such as compost, sand, leaf mold or manure -- as recommended for your plant choice and soil conditions. This is the ideal time to improve your soil texture and add nutrients it may lack.

Local extension services will help you test your soil pH to determine how acid or alkaline it is. Tomatoes for example, prefer a slightly acid pH of 6.0 to 6.8. Your extension service can also offer specific recommendations for improving your garden soil for anything you may want to plant.

Remove the loose soil temporarily and place the tire in the hole, then return the soil, tamp well and transplant your seedling into it. Remember the tire for making a "cold-frame" sits below the soil surface, so the returned soil serves merely as a small mound of loosened, enriched soil into which you plant the seedling. This creates a wall around the seedling to protect it until weather warms up.

Water the seedling well to remove air bubbles and help settle the soil around the roots. While you have the watering can, pour water into the bottom rim inside the tire until it is entirely full -- don't worry if you have some soil inside the rim. Because water will pool there rather than soak down into the ground, the rim serves as a built-in reservoir to release additional moisture for the seedling when the soil toward the center of the tire dries out. Having some soil there allows it to act as a wick. Refill this handy reservoir only when soil around the seedling becomes dry 1 inch below the surface.

Cover the entire tire in clear plastic film -- tucking loose film around the base of the tire and weighting it with soil to hold it in place -- or place a large sheet of glass over the top. An old window works well. This will help retain moisture and warmth.

Add a second tire, if necessary, as the seedling grows -- replacing the clear cover after the addition -- until the weather is sufficiently warm to allow the plant access to open air. When the weather warms, remove the top tire and plastic sheeting or glass completely to allow unrestricted growth and sunlight.

Where cool climate is not a problem -- gardeners can plant directly into the soil without using the intermediate step of a cold-frame or greenhouse -- plastic sheeting or glass is not necessary. Digging is also unnecessary. Simply place tires directly on the ground, or over cardboard or a thick layer of newspaper if grass or weeds are a problem, then fill with ordinary compost-enriched garden soil -- no need for expensive potting soil -- and plant your seeds or transplant seedlings. As the paper or cardboard breaks down, your plants' roots will push into the soil below for additional nutrients.

Add supports for tomatoes, legumes, cucumbers (Cucurbita spp.) or other climbers before planting seedlings or seeds to avoid root disturbance. Some ideas for simple supports:

Make a loop of field-fencing wire -- with a mesh size of 4 to 6 inches, for easy access to fruits when picking -- the same circumference as the inside rim of the tire and put it in place before adding soil. The wire needs only minimal fastening together as the tire and soil will keep it securely in place. This works best for bushy plants like determinate or bush-type tomatoes of short to medium height.

Drive a stake made of wood, bamboo or rebar -- concrete reinforcing rod -- into the soil in the tire and tie the plant directly to that as it grows. This is a good way to train very tall, single-stemmed plants, such as tall, large-headed sunflowers (Helianthes spp.) or amaranth (Amaranthus spp.).

Make a teepee for vigorous climbers using three or four of any of the stake materials suggested above. Simply tie the tops together, spread the legs out and push them into the soil inside the tire to secure. This is a recommended method for supporting garden beans (Phaseolus vulgaris) and peas (Pisum sativum), but also works well for cucumbers and smaller squashes.

If your summers are hot, consider painting the outside of tires white or another light color to reflect the sun before adding soil or planting in them. Start with scrupulously clean tires and use any good quality, environmentally safe exterior paint over a compatible primer for best results. For a fun look, paint tires with stripes, polka dots or other designs to liven them up.

Tires are generally thought safe for planters as the rubber is considered inert when cured. However, one scientist, Linda Chalker-Scott, Ph.D., Extension Horticulturist and Associate Professor, Puyallup Research and Extension Center, maintains that they may prove toxic to soil -- releasing polycyclic aromatic hydrocarbons --as they break down over time. If this concerns you, use newer tires and consider lining the entire inside of the tire with pool-grade plastic sheeting or an environmentally-safe pond liner as a barrier before adding soil and plants. Before filling with soil, punch several holes in the bottom of the liner to allow adequate drainage.