Monday, October 5, 2015

Dragon Fruit

Dragon fruit is produced from a climbing cactus plant known as pitaya or pitahaya; the fruit is also called pitaya. In Hawaiian it is known as paniniokapunahou or papipi pua. A famous hedge of pitaya, with its triangular fleshy stems, is growing at Punahou School on O`ahu. From July to October the hedge blooms with a wall of white flowers hundreds of yards long. This type is considered an ornamental that occasionally bears a few small, red fruits. Like many species of pitaya, it is self-sterile, that is, a plant not capable of reproducing with its own pollen. Recent breeding programs in Taiwan and Vietnam have resulted in the development of many self-fertile and productive pitaya varieties.

Since the pitaya plant blooms only at night, when many insect pollinators are not active, successful pollination is sometimes difficult to achieve for adequate fruit bearing.  Moths and bats are the likely pollinators for pitaya plants.  If moth and bat populations are low, pollination will be limited; some backyard enthusiasts have resorted to hand pollination.

To help with pollination, gardeners can turn outside lights on in order to attract moths in the evening during the bloom period.  Heavy rainfall during this time, would cause a lack of moth flights, and therefore, poor fruit production. For good fruit production, it is important to choose the right variety.

Dragon fruit plants prefer a warm, moist climate with rich organic soil. It is not suitable for areas with extreme high temperatures and intense sunlight. The plant will tol­erate short exposures to freezing temperature and will re­cover rapidly. It requires 25-50 inches of rainfall annually. Excessive rain can cause flower drop and the fruit to rot. Commercial plantings of pitaya can be found in Vietnam, Taiwan, Malaysia and Israel. 

Above photos by Forest and Kim Starr 

                                                              University of California Cooperative Extension

Monday, September 28, 2015

Composting: Get Good Results

By following some simple rules you can speed up the processing time and produce good compost in one to two months. Some ‘experts’ can even turn a pile of garden waste into nice compost in as little as 14 days.  Here are the essentials:

A. Proper moisture and air (oxygen) content - Compost works best if the moisture content of the materials is about 50%. That’s not easy to measure, but it has been estimated to be about the moisture content of a wrung-out sponge.  If the material is too dry, decomposition will stop; if too wet, oxygen becomes limited, decomposition slows and foul odors will be produced.

B. Proper carbon/nitrogen ration - For effective composting, the raw materials must have a proper carbon/nitrogen ratio – set at about 30:1.  Since this cannot be easily measured, experience has shown that mixing equal volumes of green and brown plant material will give this ratio. The 'greens' are fresh, moist materials like grass clippings, weeds, manures and kitchen scraps. The 'browns' are dry materials such as twigs, wood chips, straw, saw dust and paper.  If a pile of twigs are thrown to the side, they will eventually decompose. But when leaves (greens) are combined with the twigs (browns) in the proper ratios, the organic matter will decompose more quickly.    

Mixing the greens with the browns is not only good for obtaining the proper ratio, but also helps to maintain a good oxygen level.  Grass clippings alone (shredded paper too) tend to mat and exclude oxygen.  Adding twigs helps to open the pile allowing a better movement of air.   

C. Proper size of material - Soft, succulent plant tissue does not need to be chopped into small pieces because it will decompose rapidly.  However, the harder to decompose woody materials will compost best if pieces are ½ to 1 ½ inches in size: the smaller the pieces the quicker the decomposition.

D. Proper pile size - The size of the compost pile is important.  The minimal size is 3 cubic feet (3x3x3). Maximum size would be around 5x5 and as long as you want it.

E. Proper turning - Turning the pile is not required, but will certainly speed up the process; turn any time from every day to every10 days. Turning helps ensure proper air circulation along with good moisture and heat distribution. 

Finally, here’s how to know when the composting process is finished: when the majority of the pile has become dark, loose, crumbly and sweet smelling.  Also, the original ingredients will not be recognizable with the exception of a few pieces of tough woody material. Composting is a good way to reuse our natural resources, recycle nutrients and add good organic matter back into the soil. 

Monday, September 21, 2015

Healthy Soils

Healthy soils are full of life. This life is comprised of literally millions of different species and billions of individual organisms both large and microscopic. Forty million bacteria can fit on the end of one pin. Other microbes include algae, protozoa, yeasts, fungi and nematodes. Some of these organisms feed on dead organic matter, while others feed on other microorganisms. As a group, they help to recycle nutrients, build the soil structure and most important, help to convert organic matter into rich, stable humus. It is the humus which is the life support system of the soil.

The following soil problems can be corrected by adding humus:

1. compacted soils,
2. fluctuating pH levels,
3. infertile soils,
4. sandy soils 
5. clay soils and
6. in addition, a soil rich in humus will help reduce pest insects and disease pathogens in the soil.

How do soil organisms build better soil? 
Bacteria – feed on organic matter, store and cycle nitrogen and decompose pesticides.

Fungi – some feed on dead organic matter like crop residues; others are parasites that attack other microbes. Some live in association with plant roots delivering nutrients to the plant.

Protozoa – eat bacteria, fungi and algae. The consumption of bacteria slowly releases nitrogen into the soil. Protozoa also convert organic nitrogen, not available to plants, to nitrogen forms which are available.

Mites – decompose organic matter.

Nematodes – these microscopic worms eat other worms in the soil and are an important part of the nitrogen cycle. Some nematodes attack plant roots but most are non-pathogenic.

Earthworms – expel partially decomposed organic matter which produces  nutrient rich casts. In addition, the worms create some small tunnels which aid in the development of good soil structure and water movement in the soil.