I’m curious how common it is for vegetable gardeners to replace soil in raised beds, rather than simply amending it.
I built three brick beds (roughly 12’x3) 15 years ago. Originally they were filled with bulk bed mix from a local nursery. Over time they’ve produced wonderful tomatoes, garlic, lettuces, peppers, beets, broccoli, zuchinni, potatoes, fava beans, chard, onions and all types of herbs. Over time, I’ve amended the soil with bagged mixes and manures. By Year 12 or so, garlic crops suffered heavy rust. The tomatoes also have been less healthy, with wilt and poor quality fruit. I’ve tried to rotate crops, but in 3 beds it’s not optimal. I suspected the soil was to blame, but don’t know.
The last three years, I’ve planted only herbs, and let the rest of the beds go with wildflowers, and nasturtiums, while I’ve tackled other projects. (Now I think I need a beehive…) I’d like to get the garden back into fruit and veg production in 2020, but am wondering about the soil-- should it stay or should it go? I need to re-line the bed bottoms with wire to keep out gophers. Should i amend the existing soil and put it back in?
Thank you for any insights and suggestions.
If I had to take the soil out anyway, I’d absolutely replace it! Great opportunity. Put the soil on your non-veggie areas of the yard.
You’re forgetting two important rules…crop rotation, and letting the land lay fallow every so many years!
Add cover crops, also.
Or, you can change the soil out if that makes you happy…
Here’s a thought. Don’t replace the soil. Extend the height of the beds (it need not be brick) and bring in new soil to put on top of the old. As you age, and I speak from experience, you won’t mind having access to your crops that doesn’t make you squat quite so far. I should start taking my own advice, and maybe this year I will!
It would probably be more efficient for me to just start over, but I don’t. My growing media is just wood chips broken down with urea and a few dribs and drabs of micronutrients mixed with diatomaceous earth and a few shovels full of peat moss. So we aren’t talking about the long bucks.
Instead I amend it based on soil tests. You still have the issue of crop rotation doing it that way.
I’ve had good luck adding a couple of inches of new stuff at the top. I think that’s because I’ve gotten more adept at spiking the compost pile with just the right amount of micronutrients based on the tests.
Tomatoes often get Verticillium wilt caused by soil-borne fungi. You don’t want that infected soil near most of your fruit trees (although some, for example, figs are immune to it).
As said above, but I will mention again…
I’d keep the soil as there is plenty of good left in it I am sure. That said, I’d add a very healthy amount 4"-6"of compost, preferable a well blended mix of various types such as Horse, Chicken, Homemade, Worm Castings all combined to get as many different microbes and nutrients as possible. In addition to the above, either get a soil test done for the existing soil (~$15-ish from extension) to determine if should also mix in some additional nutrients via Rock Dusk, Sea Minerals, Kelp etc. Again, based on the soil test, making sure your Calcium levels are good as well via a source of Calcium Carbonate etc.
Once you do the above, to some level, do at least a half a season of Cover Crops, using a good blend of Fixers, Organic Matter \ Green Manure, etc seeds. If you get pre-coated seeds then you can save a step of innoculation.
Finally, add a really good quality mulch to protect the soil from the weather\sun etc so it can rebuild itself.
Thank you all for your suggestions and a lot to think about. I’ll keep you posted how this project turns out. Much appreciated!