Q.How To Improve My Soil This Close To Planting??
I’ve built two raised beds and they will be on top of a very clay soil, however I think I picked a good spot that is somewhat fertile. Now I will be getting soil poured in the next couple of days, a mixture of soil, compost, and sand. I want to know what I should do before then. I’ve picked most of the rocks out and I’ve tilled the soil to about a foot and a half. Should I leave the remnants of the weeds and roots for organic material? I’ve heard about laying cardboard or lawn cuttings underneath the new soil to smother weeds and for organic matter, but i will be planting and transplanting in just a couple of weeks. Will this tie up the nitrogen in the soil? Should I throw the weeds out? Should I add eggshells before or after? I will be planting herbs, vegetables like tomatoes and zucchini, and some flowers like echinacea and foxglove. What should I do to improve my soil, this close to planting???
First let's clear something up: eggshells belong in the compost. The calcium in shells is not available to plant roots and shells take a long time to decompose. Remove weed roots; many weeds will grow back even after tilled. In fact, the tiller chops weeds into pieces and each root piece may start a new plant. Also remove weed flowers. The rest can be left if you wish. It will tie up a small amount of nitrogen, the amount directly related to how much material is left in place. Clay is often nutrient rich and it holds water which is helpful during dry spells. Putting a barrier between the raised bed box and soil isn't a good idea because your plants will send roots into the clay soil. It takes cardboard over a year to breakdown depending on how thick it is. It also may contain chemicals in the printing ink and glues used to hold layers together. There is a simple soil percolation test you can do. If it shows the drainage is poor, there are ways to amend clay and improve drainage. Links to the test and amendments follow.