Northern Greenhouse

Northern Greenhouse

Bob's Projects & Ideas

Open Air Mulched Tire Garden

Please see info at the bottom of this webpage regarding tire safety.

I am always looking for better ways of raising plants in this harsh climate. (In 1982 we had less than 2 months between frosts.) Beyond the Arctic Circle in the northern Canada I head of people growing plants in old tires. Even in the summer the soil is frozen beneath due to permafrost. Tires filled with soil warm up and thaw faster in spring. I became a convert.

Strawberry Tires

I put out car tires in long neat rows with strawberries in each one. They warm up quickly. I put deep mulch between the rows which "buries" the tires giving them a low, unobtrusive profile. The berries drape over the rims and are easy to pick. Soil is not piled in the tire because raising the strawberries would expose them to winterkill in our 35 below zero winters. Instead the tires' hollow centers catch the snow providing winter cover.

Vegetable Tires

From the tire shops and gas stations I gathered uniformly sized truck tires (car tires are for the strawberries) which are about 3 feet across. They are neatly arranged in a 30 by 36-foot rectangle with the outside perimeter completely enclosed by tires stacked two high. All paths are one tire wide (3 feet) and are excavated 18 inches deep with the soil used to fill tires.


Soil Temperatures

The greatest benefit is that the elevated soil warms up fast in the spring due to the air contacting the massive surface area of the tire's perimeter. Also the black rubber acts like a solar collector and absorbs heat readily. I have found empty tires on sunny days too hot to touch. The rubber channels the heat to the several hundred pounds of soil inside each tire promoting root growth.

Controlled Production

Mel Bartholomew (Old Field, NY, 11733) has in his book "Square Foot Gardening" developed and refined the idea of producing massive amounts of vegetables by planting in blocks while using far less space and work than conventional rows. Some people plant too much, leading to a neglected garden. Using tires helps control your planting since each 3' diameter truck tire contains 2 sq.ft., which will hold say 3 cabbages or peppers, carrots, or beets. Spacing will vary with variety and area. Plants will cover the rim. Now you can know in advance your yield. Example, plant 12 tires of carrots for one carrot per day of the year (365). Or you can plant one tire a week for successive crops such as lettuce.

Path Benefits

The sunken paths are covered with one foot deep mulches such as straw, hay, leaves, and manure; actually permanent compost piles 'in situ'. Worms & beneficial flora & fauna grow luxuriantly. Plant roots come down from inside the tires & greedily gorge themselves. Vast amounts of water are soaked up during the rainy season with no erosion, yet evaporation is minimal from the covered soil. Being confined by tires the paths are easy to keep neat. And no mud will ever touch your shoes again! Animals & kids are less prone to mash & mangle your precious plants as they are 'contained'.


Compacted soil excludes vital soil air. Sunken paths eliminate walking on the seedbed, keeping it loose.


The tire rims and sides present a large impermeable surface markedly reducing water loss. Since exposed soil loses water rapidly in hot weather, heavy mulching cuts this substantially. Now my soil can go without water for a month in hot weather. Plant roots quickly penetrate and invade the heavily mulched sunken pathways sucking up the large reserves of water. Many roots grow on TOP of the soil I've noticed, beneath the straw drinking in the water and the nutrients from the mulch. Some go for 20 feet.

Mulching Now Possible in Cold Areas

By March our soil is frozen solid to six feet down. Heavy mulches help to lessen that depth of freezing, but also retard soil thawing and warm-up in May. However I have found the black tires grab the sun's heat and warm up the soil from below as well as the top. I can leave the thick mulches in the pathways year round, on the tires, and around the plants.

Look Ma, No Weeds!

What weeds? The heavy mulching in the sunken rows eliminates them (once you have killed your perennial weeds). The rubber sides & rims of the tires are inhospitable to weeds. Mulching the growing area at the top of the tire prevents weed seed from getting a foothold. With permanent mulches you never have to dig your soil again which brings up weed seeds from years ago.


Identically sized truck tires look neat and tidy when arranged in some orderly pattern. If your friends are not receptive to new ideas you can "hide" your tire garden by planting a hedge of Jerusalem artichoke tubers around them. (They are dense, 7 feet high, fast growing, strong, and perennial. They survive our cold climate, are excellent food, with no starch, rich in nutrients, and produce 3-5 times more than potatoes.)


The tire height (especially if stacked three high) combined with the sunken paths minimize bending. Tomatoes, cucumbers, peas, beans, and squash hang down the sides attractively.

Throw Away Your Plow, Shovel and Fork!

I plant my seeds on TOP of the soil (beans, peas, squash, lettuce, beets, carrots, onions, cabbage). Digging just brings up weed seeds. The worms aerate the soil with dozens of holes per square foot beneath the mulch, which they just love. I pull back the straw, sprinkle the seeds on the soil surface (which is loose, black and moist due to the mulch) , and gently cover with a thin layer of mulch to prevent drying and protect from the birds. Due to the warm tire soil the seeds quickly push through the mulch. Mulch from the pathways, are added to the plants as they grow larger, to suppress weeds.

Potatoes Without Digging

I got the following idea from an old book I read 20 years ago which mentioned that some Irish grew potatoes on their rocky land in rock lined trenches covered mainly with seaweed. I fill a row of tires with soil. I place another layer of tires on these. I place the potatoes on top of the soil and cover with mulch (no soil). As the potato shoots come through I add more mulch thru the season till I get layer upon layer of potatoes, all clean, no dirt! You can easily sneak out a potato and leave the rest to grow. Watering is minimal since these gourmet potatoes grow in mulch.

Where Are The Bugs?

I find heavy mulching in tire gardening produces healthy plants with little disease or pests. Water stress is less. Nutrients are copious. And there are many other reasons.

Free Miniture Greenhouses!

The best is last. Protect your precious tomatoes, squash, and cantaloupe for pennies. Stack your tires but do not fill completely with soil the top one thus leaving at least 4 inches from the top. After planting cover the tire at night with plastic or plywood or glass to keep heat in. on cloudy days cover with glass or poly. I nail our woven poly onto a frame. Our poly helps prevent leaf burning and is safer than glass. Black tires are ideal as the black absorbs the heat and the 200 pounds or so of soil in a truck tire holds a lot of heat at night. Sure beats building cold frames all winter! And they never rot! I scatter individually tires around the property to start my squash and other vine crops. Then after the great start under the poly they spread out like a giant octopus from under the mother tire. Manure in the tire gives extra growth. CAUTION: Never ever leave a piece of poly or glass completely covering the tire on a windless, cloudless, sunny day, even if it's cold outside. The temperatures can reach over 120 degrees F. in minutes. Push back the poly or glass a bit for circulation. A tire greenhouse is very, very efficient.

Are Tires Safe?

After phoning some government agencies, I can find no evidence that unburned tires pollute or are hazardous to the soil. Most say it is the fact that tires are so chemically stable (unless burned) that makes them a problem at dumps. By recycling I help our environment. You can check it yourself before deciding. I eagerly solicit any articles or evidence relating to this topic.

Bob's Greenhouse Tips

Caution About Tire Gardens

NEVER put tires in or on or near houses, outbuildings, or other flammable structures! Tires can catch FIRE and they can BURN very HOT!

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