We’ve noticed that often times people in South Florida aren’t sure what their garden is supposed to look like during the peak of summer. Even though it might be clear that we can’t grow typical veggies like kale and cucumbers this time of year, there are a few different approaches to managing a garden during the “off season”. Knowing how they all play out and how they can be combined is the challenging part for beginners. In a nutshell there are two main options: either keep growing useful plants or give your soil a rest for the 3-4 months when the weather makes gardening extremely challenging. In the following paragraphs we’ll discuss the various options and materials you might need to get, with links to where to find some of the materials locally and online.
If you’re going to continue growing plants there a few key things to keep in mind. First and most important is to cover the soil surface with a thick layer of straw around your plants. The straw acts as insulation from extreme temperatures, it protects your soil from erosion and compaction during hard rain storms, it keeps weed pressure under control during a time when weeds tend to get crazy and last but not least it assists in the soil building process by decomposing and feeding soil life. Pro tip number one: search for animal feed stores near you to find a convenient source of hay or straw. Pro tip number two: straw might be hard to come by so if you have to buy hay ask for “Coastal Hay” which is the lowest grade of the hay options (the difference between straw and hay is that hay is more valuable for feeding animals because it is higher in nutrients. For gardening we would prefer straw because it has less seeds in it and it’s typically more affordable, but it is hard to find because there are fewer uses for it). The second most important thing to keep in mind is that pest pressure is particularly high between June and September due to consistently high temperatures and humidity levels even through the night. You will need to be vigilant and have a tool kit ready for managing pests. We recommend being prepared with BT (Bacillus thuringiensis) for worms and Sluggo for snails and slugs at the very least. Another characteristic of summer weather are longer, sunnier days and increased rainfall, all of which lead plants to grow super fast and super big. Your garden will need regular pruning and harvesting. A lot of the popular summer crops like amaranth, okra and eggplants need to be harvested very often in order to stay productive. When they become overgrown they quickly go to seed and stop making food for you.
The last thing to keep in mind is that since you are not resting or dramatically building your soil it will need some TLC in the Fall. You will want to add some new soil, a bit of compost if you have access to it and fresh fertilizer before planting your Fall crops. You may also experience some cross over pests in the Fall so prepared to deal with those. If you saw aphids or white fly in your summer garden you will need to be ready to find them again on your Fall crops. Nematodes are probably the biggest issue when it comes to pest build up. Nematodes are microscopic parasitic worms that inevitably kill plants by destroying the plants root system. They are most active in warm soils and they target plants in the okra family (which is the hibiscus family so it also includes cranberry hibiscus and roselle) as well as the nightshade family (which includes eggplants, tomatoes and peppers). There are no known organic pesticides to take care of nematodes so the best thing to do is practice preventative management. If your soil is particularly dry and sandy avoid planting those target plant families, especially during the summer when temperatures favor nematodes reproduction. Add fresh organic matter in the from of new soil or compost before planting new crops to dilute the nematode population. Vigorously disturbing the soil between plantings also helps to dilute the nematode population. If you have planted okra or tomatoes (the nematodes favorites) make sure to rotate your next planting to something that nematodes don't affect as hard, for example rosemary or other hardy herbs or try a series of very quick maturing crops so that you can change them out often enough to stay ahead of the nematodes, for example arugula, baby lettuce or bush beans.
If you decide to give your garden a rest you will need to choose between two further options. You can either cover crop your soil or make it fallow and cover it with straw or plastic (or any number of other comparable materials such as cardboard, agricultural landscape fabric or mulch). The goal is to make sure your soil is not bare and exposed to the harsh summer elements that can heat up your soil, erode it, compact it and have it be covered with pest ridden weeds. Cover cropping is the most pro-active option and will require a bit more work than other options, but in turn it stands to provide the most productive results for your soil. The two common cover crop varieties for subtropical climates are sunn hemp and buckwheat. We recommend using them in unison, but if you have to choose one it should be sunn hemp. Also known as Crotolaria (it’s botanical name is Crotolaria Juncea), sunn hemp grows fast and can be up to 10 feet tall, making it the best option for controlling weeds and protecting the soil surface. It’s size and high fiber content also make it a very effective organic matter builder. Since it is in the legume family the root systems of sunn hemp actually build up nitrogen nodules that become pant food for your next crop. If you are interested in planting a sunn hemp cover crop and would like more information, watch us plant sunn hemp in our demonstration garden in this video, and watch farmer Tiff cut it down and process it after 6 weeks of growth in this video.
The most passive way to manage your summer garden is to remove all or most of the plants in it and cover the soil surface with a thick layer of straw. In the fall you will simply rake away what is left of the straw, add some fresh soil, hoe it all up a bit, add fertilizer and you are ready to plant. Although you can use many different materials to cover the soil surface, we highly recommend straw because it insulates and passively feeds soil life throughout the long hot summer months.
A raised bed planted with summer friendly crops and heavily mulched with straw in between plants. Planted here: orange mint, lemongrass, spicy peppers, asian eggplants, cranberry hibiscus & garlic chives.
A raised bed planted densely with Sunn Hemp cover crops. these cover crops were seeded about 3 weeks before this photo was taken, and will be removed and incorporated into the soil at 6 weeks old.