August is one of the hottest months of our tropical climate growing season, as you must feel every time you step outside your door. If you have a raised bed vegetable garden its likely either completely empty or its got a few struggling herbs hanging on, meanwhile your perennials and tropical fruit trees are likely thriving and growing like teenagers. If you haven't planted anything summer friendly yet its definitely not too late. September is the second rainiest month of our season (June is the first) so theres still lots of humidity and rainfall ahead of us to help establish your banana circle or mango tree (check out our July blog post for more info about designing and planting a food forest for your backyard).
The main focus of your August gardening to-do list should be resting. Not just laying on the couch resting, but allowing your soil to rest, and be revitalized. That doesn't mean just ignoring your garden, on the contrary there are a number of techniques you can execute in your garden to help the soil rest and regenerate its nutrients so that it will be at its very best come fall.
This is a made up term for a technique that we have adapted from the popular "lasagna gardening" technique for building new garden spaces. In lasagna gardening large layers of organic material are stacked on top of each other (like making lasagna) on top of bare soil to build new soil. This technique takes patience as you then have to wait for the whole steamy pile of hay, manure, mulch, grass clippings, kitchen scraps, newspaper and whatever else you've added to compost and turn into soil before using it. To use this technique as a soil conditioner for your raised bed you shrink the whole system and make a "lid" of the ingredients on top of your preexisting soil. We typically add a layer of leaf litter, a layer of old plant material, a layer of horse bedding and then top it off with a nice thick layer of coastal straw. Not only does this protect your soil from being washed away during the heavy rains of summer, it will also suppress weeds, keep your soil life nice and protected (the earthworms and fungal residents will appreciate being protected from the extreme heat) and of course the main purpose of this is that when the summer is through and you are ready to replant for fall most of the material will have composted right in your garden and turned into new soil and organic nutrients.
It might not look like much in this picture but these beds aren't "empty" they are full of composting organic material protected by a layer of hay, which will keep weeds from sprouting and taking over.
Cover cropping is a very important tool in regenerative agriculture that you can adapt to your backyard garden to help build new soil during the off season, which is now! August is the perfect time to plant yourself a cover crop, watch it grow, and chop it down so that it can decompose and leave your garden perfectly ready for fall. There are many benefits to planting a cover crop. Firstly, the complex web of life that exists in your soil, from worms and bugs to fungus and bacteria, like having roots around to live in, so having live plants in your soil at all times benefits the soil life you've built up over time. Secondly, cover crops suppress weeds by crowding them out, and they protect your soil from erosion by slowing down the movement of water through your soil. By far the most important benefit to sowing cover crop in your raised beds is that once you cut them down and either smother them or incorporate them into your soil you are using that plant material to build new organic matter in your garden. Its basically growing a plant just so you can compost it!
Here in South Florida we primarily use buckwheat, sunn hemp & cowpea to cover crop. Buckwheat is like cover cropping for beginners since its short (30 days), easy to cut down and quick to decompose. Sunn hemp is a bit more involved (because it can get away from you if your timing is off) but it has an added bonus of being a nitrogen fixer. What is a nitrogen fixer? Im glad you asked! All plants in the legume (bean) family form a symbiotic relationship with a bacteria in their root systems that uses the plant to remove nitrogen from the atmosphere and then sequester it in the soil in the form of nitrogen nodules. To over simplify this process: these plants basically make you organic fertilizer! Not only that but when you cut them down and incorporate them into your soil (at around 45 days) they will also become nitrogen.
Figuring out how to use cover crops in your raised bed can be intimidating so if you'd like more info on the process head to minute 50 of our summer gardening virtual workshop on YouTube where farmer Chris of French Farms and I take a tour of his cover cropped fields and talk about the process. If you are ready to give it a try and need to buy seeds we sell both buckwheat and sunn hemp by the pound. Stop by our nursery any Saturday from 10-5 or if thats too far Urban Oasis Project sells it for us at their farmers market booth at the Legion Park Farmers Market every Saturday from 9-2pm.
Young sunn hemp in a raised bed. It will grow for another month and get almost shoulder high before you cut it down and either cover or incorporate it.
Buckwheat flowers quickly and kills itself after producing seed, making it easier to handle but less long lasting than sunn hemp.