Create healthy soil in your own backyard

by Diana Duff

If you are thinking you can’t grow food in your garden, think again. Many Kona residents don’t plant edible gardens believing they haven’t got good soil. Yes, we are soil-challenged here, but help is just a few months of easy recycling away.

We all have rocky soil. At lower elevations, soils are not only rocky but can also be dry and alkaline. At upper elevations, rocky soil is often wet, sometimes boggy, and acidic. No can grow? Wrong. If you think “no can,” try again. Since we are all on the sustainable path, composting presents a solution to two issues we face: recycling waste and building soil.

You can get started toward your gardening goal by getting some beds defined and laying in a passive compost pile that will give you a good soil base, alive with microorganisms. Use those pesky rocks to create borders for your beds, and then start piling garden waste into them. Cut material into small pieces for fast breakdown. For a base of decomposed waste in several months, mix dried leaves, leafy prunings, grass clippings, weeds (without seeds), broken up twigs and branches less than 1/2 inch diameter. If you live in a dry area, dampen the pile and cover it with a tarp or black plastic to maintain a dampness level comparable to a wrung out sponge. In wet areas, covering can help keep the pile from getting waterlogged, which can lead to smelly anaerobic decay. In any case, a balanced mix of organic inputs including green matter for nitrogen, brown (dry) matter for carbon, air and moisture speeds the process. After sitting for several months, you’ll have a base of decomposed organic matter. Mix in some of your rocky soil to improve aeration and you are ready to plant.

Meanwhile, get started on active composting to amend the soil. For small families without space for an outdoor compost bin, composting with a worm bin is the perfect solution. See the column on worm composting from Oct. 10 describing this way of turning kitchen waste into a soil amendment. For those with more waste and an outdoor space for a 3-foot-square bin, backyard composting is a good addition. A highly productive compost bin is ideally 3 feet square (or round). When properly layered and maintained, this size container can produce a good supply of usable compost within three months.

Free local classes are being offered that teach composting techniques and give bins away to those taking the class. You can also make your own bin and get similar results by following some simple guidelines. With some recycled pallets or fine mesh fencing you can build sides for a compost bin inexpensively and with little effort. Check online for videos and instructions for creating attractive as well as useful bins from a variety of recycled materials.

Four ingredients are important for rapid composting to take place:

– Nitrogen. Referred to as green matter, it is often green and damp and can include kitchen waste, fruit and vegetable peelings, wilted or rotten produce, fresh grass clippings, green leafy prunings, weeds and even chicken manure. Meat and dairy products should not be used in backyard bins, however.

– Carbon. A balance of nitrogen and carbon are important to the composting process. Carbon, or brown material, includes dry matter like leaves, straw, small twigs, wood chips, shredded newspaper, as well as shredded office paper or cardboard. Topping additions to your bin, with browns helps seal the pile a bit and ensures a nitrogen and carbon balance.

– Moisture. The ideal compost pile is damp but not wet. If it is hot or dry, you may need to sprinkle the pile with water. If the pile gets too wet, add dry material, such as shredded newspaper, to absorb the moisture. Covering the pile can help maintain the proper moisture level but check frequently to be sure it’s not drying out or getting too wet.

– Air. Active composting requires oxygen. In passive piles, you need airflow on all sides, top and bottom. A layer of larger material on the bottom can help air circulation below the pile. For active piles, weekly turning to introduce oxygen to the core of the pile will encourage it to heat up and decompose quickly.

Recycle Hawaii is offering composting classes Saturday in Waikoloa and Kainaliu. Check the calendar sidebar for more information and download a backyard composting brochure at

Tropical gardening helpline

Pedro asks: I was recently traveling in Southern California and saw some beautiful apple orchards. I want to grow some apples. What varieties can I grow here in Kona?

Answer: Most apple varieties, like stone fruit including cherries, peaches and apricots, require a chill factor in order to set buds in the spring. The chill factor requires temperatures below 45 F for a set number of hours. We don’t really have this kind of a chill occurring below 3,000 or 4,000 feet in West Hawaii.

However, several semitropical varieties can be encouraged to fruit here if grown above 1,200 feet in elevation. You may need to trick the trees in order to get blossoms if it doesn’t go below 45 degrees at your house. One trick involves placing 50-pound ice bags on the roots for several nights in a row during the coldest part of the year.

Steven at Anuenue Gardens in Kainaliu is the only westside nursery that sells tropical apples. He orders three varieties of bareroot apple trees every spring. Ein Shemer is an early producer and a self-pollinator needing about 350 hours of chill. Golden Dorsett is the most popular and is reported to need about 250 hours of chill. Anna requires the same chill factor, and like Golden Dorsett, produces best when planted with other varieties.

You might want to consider growing the truly tropical mountain apple instead, which is native to Malaysia and was probably brought here by early Polynesian settlers. The fruit is about the size and shape of a pear and ranges in color from light pink to ruby red. Some varieties are sweeter than others but all are juicy and crisp. The flowers make a spectacular display of spiky, fuchsia blossoms usually in late spring.

Duff is a plant adviser, consultant and an organic farmer living in Captain Cook.

Gardening events

– Wednesday and Saturday: “Soil Improvement with Biochar” meets with Josiah Hunt from 6 to 8 p.m. Wednesday at the North Hawaii Education and Research Center in Honokaa. “Biochar Production and Application” meets with Hunt from 8 a.m. to noon Saturday at Jackie and John’s farm in Onomea. Part of “Practical Ag for Hamakua” series, the fee is $10 or $4 for seniors/students for each event. For more information or to register, contact Donna Mitts at 936-2117 or

– Saturday: “Backyard Composting” meets 10 a.m. to noon at Waikoloa Community Church and 2 to 4 p.m. at Anuenue Gardens in Kainaliu. For information or to register, contact instructor Piper Seldon at or call Recycle Hawaii’s Hilo office at 961-2676.

– Ongoing: Plant advice lines — consult with Master Gardeners and Tropical Gardening advisers from 3 to 6 p.m. Mondays at the Kona Outdoor Circle at 331-2426 or 9 a.m. to noon Thursdays at the University of Hawaii Cooperative Extension Service at 322-4892, and Tuesdays and Fridays at UH CES in Hilo at 981-5199.

West Hawaii Today – Features > Create healthy soil in your own backyard

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.