Is it Good or Important to Place Weed or other Barrier Materials Under Grow-Boxes?

Q.  I am laying out my new Grow-Boxes.  It was said that Grow-Boxes can be built on asphalt.  I’m putting them on dirt but I wondered if I could put weed barrier down, to prevent weeds from coming up in the boxes and also in the aisles.  Do the plants need more root depth than the 8″-deep box or is it fine to put the black weed barrier down at the bottom of the box?

A.  The general rule for garden preparation is – REMOVE ALL WEEDS and other materials, down to the bare ground.  Therefore, if it is possible you should  – with shovel, hoe, rake, tiller, or whatever you have – dig up and remove all weeds (and grass is a weed in this instance, since Dr. Mitt’s definition of a weed is “a plant out of place”), including the roots, rhyzomes, and runners of all perennial weeds. 

Remember, you are investing in creating a long-term garden, and if it’s done properly it will feed you for many years, so do it right the first time.  Dr. Mittleider says “No amount of scratching after the crop is planted will overcome the ill effects of poor seed-bed preparation.”

When the proper preparation is done you shouldn’t need to put any weed (or other) barrier under your container garden.  However, healthy plants and excellent crops CAN BE GROWN in the 8″ Grow-Boxes, even if they are on top of concrete or asphalt!  So, while the ideal situation would be to allow your plant roots access to the native soil to pick up additional nutrients, it isn’t mandatory.  To illustrate, let me give you a current example, which some of you may even be able to see for yourselves, and for the rest I’ll post some pictures in the Photos section.

Jacob and Mildred live in Redlands, California.  Jacob can’t keep his hands out of the dirt, so upon moving there in 2003 he immediately began growing vegetables in every available spot.  The owners of the assisted-living complex were so impressed with the beautiful plants, they gave him a spot of his own and paid for 20 Grow-Boxes and T-Frames, so he could have a “real” garden.

However, when he tried to grow last year the gophers drove him crazy AND termites attacked his plants, so that he lost over half the crop.  To solve both problems Jacob covered the entire garden area with 1″ chicken wire, and then laid down asphalt roofing material on top of that – all before placing and filling his Grow-Boxes. 

Jacob now has a wonderful garden growing, with no termites and no gophers – right through the winter – and everyone loves it!  So, there are times when putting something under your boxes is not only appropriate, but even necessary.

P.S.  Dr. Jacob Mittleider died in May, 2006.  We mourn his loss, and only hope to carry on and spread his priceless legacy of gardening knowledge.

P.P.S.  The Mittleider Gardening books and Manuals teach all you need to know about this subject, and can be purchased in the Store section, or as digital downloads. 

A digital copy costs 30-40% less, and is available instantly!  I HIGHLY recommend you look here for the best gardening books available anywhere!  Get one NOW and be gardening TODAY!!