Tropical Gardening: Vegetables and annual flowers are good mates
September is just around the corner, so it is time to think about our cool season gardening.
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Also, high food costs are everyone’s headache these days. As a result, yards and lanai provide prime opportunities to help cut food expenses. You can do it by planting vegetables and flowers.
And if you’re going to a have a top-notch garden, it’s time to plan the planting layout for fall
By designing a combination, you can have an attractive spot that produces cut flowers as well as fresh vegetables. Both require regular fertilization and spraying for insects and disease, so they are naturally good together.
In selecting a plot, remember most annuals and vegetables must have a full six to eight hours of bright light per day.
Next comes the vexing problem of what to plant.
Choosing plants by heights is one problem-solving approach. Some taller growing annuals for the back areas of the garden are cleome and sunflower. Some taller vegetables to try are Hawaiian super sweet corn, trellis U.H. tomatoes and Manoa wonder beans.
In the center rows and toward the front, consider medium height plants. Tuberose, blue salvia, tall ageratum, giant dahlias, red salvia and gypsophila are examples. Vegetables include peppers, squash and Waimanalo long eggplant.
For low edging, you might use allysum, petunias, verbena, dwarf phlox or some of the dwarf nasturtiums. Wainae strain kai choi, won bok, Manoa lettuce and parsley are good varieties of vegetables to use in this space.
With up to 100 annuals and vegetables to choose from, it shouldn’t be a problem to fill the garden with many kinds of colorful and useful plants.
You can try your hand at success by using the organic approach, the conventional approach or a combination.
Organic gardening differs from conventional gardening mainly in fertilization and pest control. The organic gardener uses natural and organic materials and methods, whereas the conventional gardener will use a combination of all materials and methods shown to be safe, effective and non-detrimental to himself or his environment.
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Here are some steps to help you with supplying your vegetable needs:
• Select a plot of good, well-drained soil near a water supply. It should be close to the home for convenience but not shaded by tall buildings or trees. Enclosing the garden spot with a fence is important if you need to keep out wild jungle fowl, pheasants and pigs.
• Many gardeners find it helpful to draw out on paper the location of each row and the crop or succession of crops to be planted.
• Contact the UH Master Gardener hot line for information about vegetables suited for Hawaiian gardens, leading varieties, seed or plants needed, planting distances and depths and best time for planting.
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Since organic fertilizer and soil conditioning materials are slow working in general, they should be mixed into the soil at least three weeks ahead of planting and the soil thoroughly prepared for the seed or transplants.
Clumps of unrotted organic materials not only interfere with the seeding operation, but can result in nutrient deficiency and possible soil-borne disease problems such as damping-off of young seedlings.
Natural and organic materials that yield plant nutrients upon decomposition often are available for purchase either separately or in combination. These materials can be applied to the garden separately or combined, used in the compost pile or mixed with manure.
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Rock phosphates are natural deposits of phosphate in combination with calcium. Raw materials dug from the earth are very hard and yield phosphorus very slowly. When finely ground and with impurities removed, the powdery material is only slightly soluble in water, but can be beneficial to plants in subsequent seasons following application.
The reaction of phosphate rock with acids from decaying organic matter in the garden or compost tend to make the phosphorus available to garden plants.
A more readily available form of phosphate is treble super phosphate. Broadcast the material over the soil surface and work into the topsoil at least three weeks before planting. Manure or other organic fertilizer should be added at this time. Since the materials are so slowly decomposed, side dressings are seldom beneficial.
Potassium is widely distributed in nature, occurring in rocks, plant and animal tissues and sea and lake waters.
In gardening practices, materials such as wood ashes, banana peals, seaweed, potash salts, and ground rock potash are used alone, in combination with other materials yielding other nutrients, mixed with manure or in compost piles.
Since the potash bearing materials vary so much in composition and rate of decomposition, specific application rates must be determined for each material and its combination.
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An advantage for using organic materials as fertilizers is that they contain many of the elements also needed by the plants in addition to nitrogen, phosphorus and potassium.
Besides the general amounts of micronutrients found in most organic materials, certain ones are concentrated into such naturally occurring materials as gypsum (calcium and sulfur) and dolomite (calcium and magnesium).
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Reducing the acidity of the soil is the primary purpose for using lime in the garden. However, liming materials also provide nutrients for plant use.
Calcium and magnesium are the two elements most commonly provided by lime. Lime to sweeten the soil should be applied only when the needs were established by a reliable soil test.
Apply lime well in advance of the planting date, preferably two to three months before the garden is planted. Mix well with the soil and keep moist for best reaction.
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In irrigating the garden, it is advisable to thoroughly wet the soil once a week unless sufficient rain falls. Thus, the soil will be moistened throughout the root zone.
Light sprinklings everyday merely tend to wet the surface and encourage shallow root growth. Use of organic materials as soil conditioners and fertilizers tends to improve the ability of the soil to retain moisture.
Also, a good garden mulch will conserve soil moisture. Mulch is any material, usually organic, placed on the soil surface around the plants.
Organic materials most commonly used for mulching are leaves, grass clippings, sawdust and wood shavings. Synthetic materials, such as plastic sheeting, have been used in recent years.
Among the benefits of a mulch are that it conserves soil moisture, conserves nutrients, reduces soil erosion, reduces weed growth and provides a barrier between plant and soil. It also moderates the soil temperature.
At the end of the garden season, the mulch can be removed and composted or cut into the garden soil. Most mulch is woody and should have manure or other rich organic fertilizer applied with it when cutting into the soil.
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During periods when infestations of various garden pests are high, control by natural means becomes very difficult.
However, the following practices will help reduce losses.
• Plant resistant varieties.
• Select peat-free transplants.
• For cutworms, place a cardboard collar around plant stems at ground level.
• Spade garden early so vegetation has time to rot before planting.
• Clean crop refuse early.
• Keep out weeds that harbor insects and diseases.
• Hand-pick insects.
• Water in the morning so plants are not wet at night.
• Dispose of severely diseased plants before they contaminate others.
• Marigolds, when planted as cover crops, tend to reduce some kinds of nematodes. The use of marigolds tends to repel nematodes.
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Many organic gardeners approve of and use sprays and other preparations containing naturally occurring materials.
Pyrethrin, rotenone and nicotine are examples of natural poisons from plant parts. These give some control to some insects under certain conditions. Neem products also are valuable tools
Natural predators should be encouraged wherever possible.
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Suitable materials for growing vegetables the organic way are not always easy to locate.
Garden supply stores carry many products, especially seeds and equipment, that can be used by the organic enthusiast. However, for the difficult to find items, the gardener might have to order from specialty businesses dealing in organic gardening supplies.
For other home garden questions, call the University of Hawaii College of Tropical Agriculture and Human Resources Master Gardener helpline in Hilo and Kona.