Laidback Gardener Tip of the Day

7 Things to Do When Tree Roots Invade Your Vegetable Garden

20151101AInstalling a vegetable garden where there are tree roots in the soil is never a good idea, because the roots will quickly invade, stealing water and minerals from the vegetables, rendering planting and hoeing difficult, and making harvesting root vegetables next to impossible. And you have to put a good distance between the garden and the tree, as its roots can easily extend twice as far as its longest branches.

But what if it’s too late and your garden is already set up and full of tree roots? Here are 7 possible solutions:

  1. Start over again in an area where there are no tree roots.

This is always the best advice. Trees and vegetable gardens simply do not mix!

  1. Grow in containers.

20151101BIf you start to grow your vegetables in pots (I recommend recycling used plastic buckets for this purpose) and you give the pots a quarter turn 3 or 4 times during the summer, this will tear off invading tree roots (yes, they will try to work their way in through the drainage holes) before they can do any damage. Or place the pots on a section of geotextile to stop the roots entirely.

  1. Dig a trench around the garden to remove tree roots.

20151101CAt least the side where the roots come from. You’ll need more than a shovel to do so: certainly pruning shears and probably an ax or a saw. A trench about 1 foot (30 cm) deep is usually enough, because the tree roots tend to grow near the surface, especially those that are far from the trunk. Some people try lining the trench with a sheet of plastic or root barrier, but be aware the roots will find their way back. No matter what you try, you’ll find you’ll have to repeat this every couple of years when the tree roots start to invade again.

  1. Install an in-ground barrier around the garden.

20151101DThere is a product especially designed to keep tree roots in their place permanently. Usually called rhizome barrier or bamboo barrier, it’s a kind of semi-rigid plastic film, usually about 2 feet (60 cm) in height, that you can insert upright in the soil around the garden. Installing one is quite an effort, but it should keep the tree roots out permanently. This product is widely available in Europe and in parts of the United States, but I know only of one source in Canada: Canada’s Bamboo World.

  1. Cover the soil with weed barrier and put a raised bed on top.
How not to do it! The weed barrier was simply stapled to the inside of the wooden frame rather than extending well beyond it. Tree roots will be back in no time flat.

You can stop tree roots for a while by covering the area with two sheets of weed barrier fabric or cloth (readily available in garden centers and hardware stores), then installing a raised bed over top. The barrier has to extend well beyond the bed (about 2 feet/60 cm), at least on the side the roots are coming from. Now build a frame of 10 to 12” boards and place it on top of the weed barrier. Fill it with good garden soil… and start to plant your veggies. Cover the section that extends beyond the bed with mulch. This should give you 3 or 4 years of peace, but you will have to redo it eventually: I’ve never seen weed barrier succeed in stopping tree roots entirely.

  1. Use a Big Bag Bed.

21051101FThis is a commercial product: an extra large version of the popular SmartPot growing container. The container is made of extra thick geotextile, not the flimsy material usually sold as weed barrier. Installation is a cinch: just unfold the bed, place it on the ground, fill it with good soil and start planting. The standard model is a circle 50 inches (127 cm) wide by 1 foot (30 cm) high, but there are also smaller formats.

  1. Start over again in an area where there are no tree roots.

I know: this isn’t a new tip, but rather a repeat of the first one… but it still is by far the best advice!

12 comments on “7 Things to Do When Tree Roots Invade Your Vegetable Garden

  1. My grow bag raised bed is on a concrete patio and the tree root actually crossed over the concrete (about 12”) and got into my bed. You just can’t win lol!

  2. I intended to put down a sheet of corrugated iron then a raised bed on top. This will allow drainage while stopping the roots from taking all the water.

  3. How about cutting down the tree causing the problem, or at least the large limbs/roots leaning toward the garden plot? Might take a couple years for the problem to go away, though.

  4. In my case, fibrous roots invade with aggressive regularity from various trees near my veg garden. It’s not easy, but each year I shovel and hoe the soil, pulling out as many reborn roots as I can. If you have a rototiller, it can help grind up the invaders, at least for a season. You may want to try planting vegetables that take most of their nutrients from the first several inches of the soil. Generally, many vegetable plants root out horizontally. But be aware that certain root crops have deeper requirements making them vulnerable to tree roots. Of course, you can always cut down the trees (never a good choice), but I suspect their root system will stay embedded in the soil for many years.

  5. Audrey B

    There are few maple trees over my fence (state trees) that we believe are causing a problem for our garden. I planted tomatoes and other vegetables last year but my harvest was very poor. This year we realized the problem could be fibrous roots, not surface roots that I can see, but fibrous roots that invaded our garden planter which made us believe it’s from those maple trees. Before putting my tomatoes this year we dug up and sifted all those roots but to no avail. Our heirloom tomato plants that grow from six feet tall are only about 30″ and all the leaves are turning yellowish and wíth very little flowers. I can hardly find info on this and if it is really the problem. Is there help out there with this problem for a reasonable crop? We will be moving the plant to another area next year. Thanks

  6. Katrina Gray

    100% true for me too – much less than a year. Last fall, after roots had destroyed my garden, I proclaimed it would never happen again. I thought I was so clever using a series of 30 100-gallon grow bags, but I recently started to see those old familiar signs of tree-root strangulation: stunted growth, no fruit production, healthy plants suddenly dying. Now I’m having to tear everything out, remove the roots, place the bags on two layers of landscaping fabric and pallets, and replace the soil with expensive truckloads of compost. This should be when I’m collecting boatloads of tomatoes, okra, and cucumber, but nope!

  7. bag beds don’t work, roots will bust through in a year or so.

    • I’ve had one for 7 years now. So far, no problem, but that could depend on the type of tree growing nearby.

    • We had the same issue, and started building shelves from cheap cedar fence boards and cinder blocks. We put our grow bags up off the ground and that has solved our Insidious tree root problem.

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