Tropical Gardening: Hamakua Harvest Festival focused on healthy farming for healthy communities

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Don’t miss Hamakua Harvest Farm Festival from 8 a.m.-4 p.m. Sunday, May 29, in Honokaa.

Don’t miss Hamakua Harvest Farm Festival from 8 a.m.-4 p.m. Sunday, May 29, in Honokaa.

It will be a great opportunity to support local farmers and learn some valuable farm and garden techniques. There will be more than 40 vendors of fresh produce, nursery plants and crafts along with educational presentations about everything from making goat cheese with Dick Threlfall and grafting fruit trees by Ty McDonald with the University of Hawaii College of Tropical Agricultrue and Human Resources to “Fruit Trees of the Future” by Brian Lievens with the Hawaii Tropical Fruit Growers Association.

The day will be vibrating with music, entertainment and Hawaiian cultural activities.

For more information, contact Lori Beach at info@hamakuaharvest.org or Julia at (203) 903-1696.

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Now, let’s explore ways you can make your gardening experience more enjoyable.

Meteorologists are forecasting a continuing El Nino and that means dry weather for much of Hawaii. When weather conditions are dry, it is a good time to consider ways to conserve water.

Organic material is essential to good soil. Decomposed organic matter helps increase water and nutrient-holding capacity of the soil. Unrotted material such as leaves and clippings used as surface mulch can help conserve moisture and keep weeds under control.

Nematodes, those little microscopic worms that feed on your roots, will do less damage in a high organic soil. Organic matter might also increase the minor element and microbiological activity of your soil.

For those reasons, it is vital to save your grass clippings and leaves. They are like money in the bank. You can store these materials in a corner of the garden.

Decay of plant material deposited in a compost pile can be hastened through the use of fertilizer and manures.

For each bushel of leaves or grass clippings, add 2 cups of balanced fertilizer (composed of nitrogen, phosphorus, potassium) and 1 cup crushed coral, dolomite or hydrated lime.

Build the compost pile in layer-cake method, with layers of plant material 6 inches deep. Continue until the pile is 4 feet high or so.

After the pile shows signs that decay is well underway, usually four to five weeks, mix the pile by turning it over. A pitchfork would come in handy at this point. The compost is ready to use in about three months. It is an excellent material to mix with soil for vegetable gardens and new plantings.

Anthuriums especially thrive on compost. They love that high organic, well-aerated mix with good water retention capability, yet good drainage. A good mix needs to be able to anchor the roots and stem so the plant will not topple over as it grows yet provide sufficient moisture, nutrients and aeration to the plant. Cinder or crushed rock added to composted wood shavings, macadamia nut shells or peat or tree bark will serve to better anchor the roots.

Even with composting and mulching, you will still need to fertilize your garden.

Some Hawaiian soils are very young and low in nutrients. Larger amounts of fertilizer are needed for fast-growing plants and lawn grasses than where soils are older and better developed.

The younger soil is not only lacking in the primary elements, such as nitrogen, phosphorus and potassium, but it is deficient in the secondary elements such as calcium and magnesium. Then, there are those “minor elements” such as manganese, iron, copper, zinc and boron. Even if all elements required are there, they might not be available because of high alkalinity or very acidic conditions of the soil.

When plants are grown in these mineral-deficient soils and fertilized with ordinary plant foods, they often develop various deficiencies.

Several years ago, plant doctors studied these deficiencies and learned not only how to recognize the affected plants but also that they could be corrected by applying the minerals in which the plant was deficient.

But what average gardener has the training that enables him to recognize deficiency symptoms in plants?

To overcome this problem, the “nutritional spray” was developed. It is a mixture that contains about all of the minerals in which a plant can be deficient. This is especially effective with alkalines that are not easily neutralized.

At first, it was necessary to add lime to neutralize these solutions, but garden stores now have mixes that require no lime.

Some plants are more subject to mineral deficiencies than others. Especially vulnerable to mineral deficiencies such as dieback, mottle-leaf, small leaves and yellow leaves are hibiscus, gardenia, mock orange, ixora, mango, avocado, macadamia, coffee and citrus.

Two to three times a year is usually enough to apply a nutritional spray.

Commercial growers apply the nutritional spray as a “preventive measure.” It is easier to prevent deficiencies than correct them.

In new gardens, it might be necessary to apply a nutritional spray about every three months for the first year to keep ahead of deficiencies.

Along with the nutritional spray, it is a good idea to use a soil application of the minor elements. Magnesium, iron and zinc are the most important elements, but occasionally we find plants with boron, manganese, copper and other “trace” element deficiencies. There are several “shot gun” combinations available at your supply store.

Certain plants require larger amounts of various elements than others. As you get acquainted with our tropicals, you will find, for example, that iron is especially important on ixoras, hibiscus, azaleas and gardenias or that magnesium keeps leaves of coconut and areca palms from getting orange colored and dying prematurely. Zinc is the vital element in growing queen palms, royal palms and palms in the date group. Howea, or kentia, palms and our native pritchardia, or loulu, palms suffer from a twisting distorted growth patterns because of boron deficiency.

Increasing your soil’s organic matter and using a “shot gun” treatment of trace elements as a spray or soil application or both will keep your plants from having these deficiencies under most conditions. Remember to follow directions on the label. Too much of the important plant nutrient materials can be as bad as too little.

If in doubt about your soil type and pH, you can have your soil tested.

This information is supplied by the University of Hawaii College of Tropical Agriculture and Human Resources. For further information about soils and testing, contact the office near you.