The general rule for garden preparation is – Eliminate ALL WEEDS and other components, down to the bare ground. Consequently, if it is doable you should – with shovel, hoe and rake, sod cutter, tiller, or whatever you have – dig up and eliminate all weeds (and grass is a weed in this instance, since Dr. Mitt’s definition of a weed is “a plant out of location”), such as the roots, rhizomes, and runners of all perennial weeds.
Recall, you are investing in making this garden, and if it is accomplished correctly it will feed you for a lot of years, so do it right the very first time. Dr. Mittleider says “No quantity of scratching just after the crop is planted can overcome the ill effects of poor seed-bed preparation.”
When the right preparation is completed you should not need to have to put any weed (or other) barrier under your boxes. Nevertheless, wholesome plants and fantastic crops CAN BE GROWN in the 8″ Grow-Boxes, even if they are on leading of concrete or asphalt! So, while the ideal situation would be to enable your plant roots to go into the native soil and choose up extra nutrients, it isn’t mandatory.
Jacob and Mildred lived for numerous years in Redlands, California. Jacob couldn’t retain his hands out of the dirt, so upon moving there he right away began growing vegetables in each available spot. The owners of the assisted-living complex were so impressed with the beautiful plants he grew that they gave him a spot of his own and paid for 20 12″-higher Grow-Boxes and T-Frames, so he could have a “genuine” garden.
Even so, when he attempted to grow the initially year the gophers drove him crazy AND a illness attacked his plants, so that he lost over half the crop. To resolve plastic weed barrier covered the complete garden area with asphalt roofing material, and then laid down 1″ chicken wire on top rated of that – all prior to putting and filling his Grow-Boxes. I was able to travel to California that October and assist him with the entire project, including building and putting the boxes and T-Frames. It was a fantastic encounter functioning with him.
Jacob thereafter had a excellent garden, with no illness and no gophers – suitable via the winter – and every person loved it! So, there are instances when putting something under your boxes is not only appropriate, but even needed.