Successful gardening or farming begins with healthy soil. Healthy soil tends to grow healthy plants that can resist diseases or pests and produce healthy food or lovely flowers and foliage. Be a soil gardener or farmer first and your resulting healthy soil will grow healthy plants for you.
In Kona, with little soil available, building soil is part of the process. You don’t need to be a soil scientist to build healthy soil, you only need some time and patience and a little ingenuity. To be sustainable, try to use local ingredients that are easily available and often free. A 32-page publication that describes many ways to use locally available resources to enhance the health of your soil and thus the health of your plants is available at agroforestry.net/images/pdfs/Locally_Available_Resources_Radovich.pdf.
The introduction to this publication recommends practices that will ensure the long-term health of your soil like mulching and cover cropping. The authors also suggest that composting can provide optimal health and fertility but that short term productivity can be aided by fertilizing. Since the cost of imported fertilizers continues to rise, using local inputs to keep plants healthy and is advised.
One of the easiest things you can do to conserve the soil you have and maintain its health is to leave it alone. The no-till farming method has support from recent research and can be used in your garden as well. The second, and almost as easy, practice is to keep your soil covered. Weeds or grass will do, installing leguminous plants that add nitrogen to the soil is even better. Bare soil is a prime candidate for erosion by wind or rain and for being baked dry by the sun.
Growing weeds is far better for your soil than leaving it bare. Though grass may look nice, its maintenance requires lots of water and fertility to maintain its appearance. If you really want to become a soil farmer, plant a nitrogen fixer like perennial peanut as a ground cover or taller sunn hemp (crotalaria) or fava beans. Both the sunn hemp and the beans provide added value once they grow tall. Cutting them and laying them on top of the soil as green manure adds organic matter. In their decomposition process they’ll provide a desirable habitat for soil microbes. The resulting healthy soil is a living, thriving growing medium.
If you don’t grow your own green mulch, you can also find mulching material on your land in the form of rocks or dry leaves. Wood chips are somewhat easy to find. Anything that covers bare soil has benefits. If you can haul mulch or hire someone to haul it for you, the county is still offering mulch at transfer stations to homeowners. This mulch, created by the county from local green waste, may have the odd chopped slipper and bottle cap, but it can be a great addition to your soil as long as you check it for fire ants before you unload it and preferably let it sit for at least a few weeks or several months to further break down before applying.
Of course, we all know by now the value of composting. Not only are you turning your kitchen scraps and other green waste into a wonderful soil building additive but also you are helping to reduce the waste that goes to the dump. Compost enlivens soil with its active microbes while adding valuable organic matter, nutrition and water holding capacity.
Worms can provide composting help when you provide garbage eating worms a suitable home and feed them your kitchen scraps. Search the Internet for vermicomposting methods to choose a system that works for you.
Once you have compost or vermicompost, you can make a highly nutritious compost tea that can provide additional nutrition through a foliar spray. Making the tea requires few inputs and little effort. The finished product is a powerfully effective fertilizer. Compost tea instructions abound on the Internet.
Off site or slightly more work intensive soil enhancing practices include making bio char, collecting animal manures and growing and collecting fresh water aquatic plants for fertilizers.
Check out ctahr.hawaii.edu/sustainag/ the Sustainable and Organic Agriculture Program for more information and videos on various soil enhancing practices and to check on upcoming classes and events on soil health. To learn even more about soil watch the full length feature “Symphony of the Soil.” You can download it at symphonyofthesoil.com.
Tropical gardening helpline
Tammy asks: I have tried several times in the last few months to get turmeric rhizomes to sprout to little or no success. How can I get them to grow?
Answer: If you were trying to get your turmeric roots to sprout this winter, your lack of success was because turmeric is dormant in winter. When the days are shorter and the sun is lower in the sky, turmeric does not grow. It remains dormant for four to six months every winter.
If you have some rhizomes that you have not planted keep them in a warm, dry spot until you see the buds pop and shoots start to grow. If they start to dry out too much, you can spritz them lightly with water. That will encourage sprouting once the roots break dormancy. That should happen in a month or two from now. You may also see that the roots you planted this winter will also sprout as spring progresses.
Once you see the buds breaking and shoots starting to form on your roots, plant them in moist (not wet) soil that contains some organic matter and compost. The plants will grow well in a large pot or garden bed that gets filtered sunlight and has soil that drains well. Turmeric grows best in an environment that has adequate moisture but is never wet. The roots easily rot in soil that is too wet. The richer the soil the more rhizomes your plant will produce. A single plant can produce a large root mass to use. Be sure to save some rhizomes or leave a few in the ground to overwinter and grow next summer.
Email plant questions to konamg@ctahr.hawaii.edu for answers by certified master gardeners. Some questions will be chosen for inclusion in this column.
Diana Duff is a plant adviser, educator and consultant living on an organic farm in Captain Cook.