Local commercial landscapers often try to encourage their clients to compost green waste on site. Doing so saves gardener’s time and gas and saves the homeowner money but homeowners with small lots or a lack of information about all the benefits of composting may prefer that their plant waste be hauled away. After July 1, “away” is going to be 30 miles away in Puuanahulu. This means lots of gas and fossil fuel emissions and time will be spent to dispose of green waste.
It may be time to consider some environmentally sound alternatives. On site composting is one of those alternatives. The environmental problems of increased fuel use and resulting emissions can be mitigated by practices including chopping and dropping as well as passive or active composting. Though it has been handy to have the county process our green waste into mulch, we can do it ourselves and avoid the risk of bringing unwanted toxins, pests or diseases onto our property. Though some homeowners may deem composting as “unsightly,” being environmentally conscious and displaying healthy plants as a result could become the new normal, as well as beautiful and desirable.
Most pruning debris can be easily chopped and dropped. This practice puts mulch in place while the job is being done. It takes a few minutes to chop pruned branches into small pieces and drop them at the base of the tree or shrub being pruned. The smaller the pieces, the quicker the “instant mulch” will break down, providing moisture retention while enriching the soil around the pruned plant. The microbial activity during decomposition will improve soil and result in healthier plants and less insect and disease attacks. Time spent chopping and dropping has obvious benefits.
If you want decomposition to take place out of sight, create an area for green waste to be composted. Even if you have a small lot, you can probably find a corner or hidden area to put weeds, prunings and grass clippings. Many attractive designs for large compost bins are available online. They can be made from free pallets, wire, wood, cement block, metal roofing or other building materials and with a little imagination can be quite decorative.
Compostable waste needs to be put in a designated place where microbial activity can break it down. The rich results of a few months of decomposition can be used to mulch your plants. A few months more and the material can be completely composted and used as a soil amendment.
Though some people may worry about insects and rodents being attracted to compost piles, you can avoid most unwanted visitors by keeping the green waste separate from food waste. Successful green waste composting can be accomplished in a several ways. An active pile requires a bit more attention and will produce mulch and compost quickly. A passive pile will decompose more slowly but will still break down over time and provide you with healthy soil additives.
For active composting to take place nitrogen, carbon, air and water need to be present. This is not complicated. You simply need to be aware that green stuff including leaves, grass clippings and weeds provide nitrogen to the pile. You could also include coffee grounds and fruit or vegetable waste but those may attract pests. Twigs, dried leaves or dead palm fronds are usually brown and supply the pile with carbon. If you are short on carbon, you can add shredded newspaper or cardboard. You’ll want to have the pile be a mix of about 75 percent carbon or brown material. The green material or nitrogen is needed to keep the pile moist and the microbes alive and working. Too much green and the pile can get slimy. Too much brown and the pile can dry out and slow down. Air circulation in the pile is essential and if it gets too dry, water may need to be added to moisten the mix and keep those microbes working. Aerating the pile by mixing or turning it occasionally will speed up the process.
Simply piling up your green waste in the designated spot is called passive composting. A passive pile is less demanding but will decompose more slowly. In either case, by turning your garden into a composter you will certainly save some money and supply your garden with free nutrition. Start thinking about on-site green waste composting today to be sure you have it in place by July.
Tropical gardening helpline
Julia asks: I am having a problem with Chinese rose beetles eating the leaves on my young cacao tree to lace. I don’t like the idea of hand picking them at sunset, but a friend suggested shining a light on the tree at night might work. Since my tree is far from any electrical connections, I thought of putting solar lights around the tree. Will that work?
Answer: Chinese rose beetles are attracted by the dim light just after sunset but are repelled by daylight or other bright lights. If you encircle your small cacao tree with solar lights and be sure that the light is bright throughout the tree, it might work. Try it and see. It will probably provide at least enough light to deter some of them a bit.
Chinese rose beetles attack more than 250 ornamental and edible plants and eat the leaves in the early evening. They are about a half-inch long and usually reddish brown in color. If several of them work on a plant, they can reduce the leaves to veins only or simply make them look as though they’ve been peppered with buckshot in a single night. In any case, their feeding will reduce the leaf surface that enables photosynthesis thus reducing the plant’s food supply. Though many plants, including cacao, can resist their attacks as they mature, the health of the young plant will be compromised unless you can discourage or get rid of the beetles.
After feeding and during the day, the beetles hide in the soil at the base of plants. Some anecdotal success has been reported by applying neem cake fertilizer, which has a deterrent odor, beneath target plants.
Sunset hour picking as well as putting out homemade traps will get rid of the beetles completely. Visit ctahr.hawaii.edu/UHMG/FAQ/faq-chinese-rosebeetle.asp for information on those techniques.
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.