Wednesday, December 26, 2018

Poinsettias

This is the time of year many people have poinsettias. What to do with them after the holidays?

Care 
  • Poinsettia plants prefer indirect light, six hours daily is ideal.
    • Poinsettias require daytime temperatures of 60 to 70°F and night time temperatures around 55°F for best growth; high temperatures will shorten the life of the plant.

    • Standing water can be harmful for the plant. Remove any wrappings from around the pot or punch holes in the foil so water can drain into a saucer; discard excess water.  
    • In some climate zones poinsettias can be planted outdoors.
    Yet, some are concerned because they think the plants are poisonous. Are poinsettias poisonous? No, this myth has been around since the early 1900’s. The American Society of Florists has been trying to dispel the myth for a long time. They say that no other commercial plant has been tested for toxicity more than the poinsettia.

    According to the American Medical Association’s Handbook of Poisonous and Injurious Plants, ingestion of the poinsettia plant has been found to produce no ill effects except an occasional case of vomiting. According to the POISINDEX information source, a child who weighs 50 lbs. would have to consume over 500 leaves before he reaches a potentially toxic level. Since the taste of poinsettia leaves is reportedly unpleasant, it is unlikely that a child or animal who attempts to eat or chew the leaves, will continue to do so after the first taste. Some people, however, can develop a skin and eye irritation from contact with the milky sap of the plant.



    Saturday, December 1, 2018

    Citrus - Ripe or Not

     In tropical regions of the world, some gardeners patiently wait for their citrus fruit, such as tangerines, to turn orange before picking them.  When using color as an indicator for ripeness, the fruit can easily pass its prime, which is characterized by dry fruit segments. 

    Coloration can be an indicator for ripeness in temperate and subtropical climates like California. But in the tropics, color is not a good guide for harvesting. Large temperature differences, such as 85 F. in the day and 45 F. at night, is the condition which produces the orange coloration.  This is also true in other fruit such as apples. 
    In contract, temperatures in the tropics do not significantly vary; thus fruit tends to stay at least partially green.
     
    If you know the variety of the fruit, you can find out the harvest period. If you don’t know the variety, then when the fruit first begins to show color, pick one and taste it. If it’s not ripe, or not sweet enough, wait a week or two and pick another. Fruit will sweeten when left on the tree. Eventually you’ll discover the right time and know the approximate picking schedule for next year. 

    Once citrus fruit is picked, it will not continue to ripen and become sweeter unlike other fruit such as the banana.


    Thursday, November 15, 2018

    When Is a Yam a Sweet Potato?


    While enjoying the traditional Thanksgiving dinner, some people may ask, "What is the difference between yams and sweet potatoes?"  Are they the same by a different name? 

    Many years ago orange colored sweet potatoes were introduced to the Southern United States. In an effort to distinguish these from the traditional white-fleshed potato, producers called them yams, which is the Anglicize African word, nyami.  Today, most of the starchy tubers consumed in the US and labeled as yams are in reality sweet potatoes. Yams and sweet potatoes however, are not the same; in fact, they are quite different from each other. 

    As far as botanical order is concerned, they are at opposite ends. The sweet potato is a dicot, set in the morning glory family. Yams, on the other hand, are a monocot, closely related to grasses. The sweet potato, whose sweet and moist flesh varies in color from white to yellow and orange, is native to South America; the skin is typically smooth. In contrast, yams are dry and starchy and rather bland. While yellow or purple in color, the skin is rough and a bit shaggy. Yams are native to North Africa and Asia. They range in size from that of a small potato up to 150 lbs. Yams are a primary agricultural crop in West Africa, where 95 percent of the world's yam crop is grown. 

    Garnet, Jewel, and Beauregard are orange fleshed sweet potatoes that  masquerade as yams in the local supermarkets.


    Tuesday, October 30, 2018

    Why Squash Plants Produce Lots of Bloom But Little Fruit


     
     Squash, along with melons and cucumbers belong to the same plant family called cucurbits (cucurbitaceae). These vegetable plants bear two kinds of flowers on the same plant, male and female.  In order to produce fruit, the pollen from the male flower must be transferred to the female flower. Since the pollen of cucurbits is sticky, wind-blown pollination will not occur. Instead, insects do the major pollination work –honeybees being the main workers.  So, if bees aren’t frequenting your garden, for whatever reason, the fruit set on your squash, cucumbers and melons will be poor. 

    Hand pollination, although a tedious chore, can be accomplished by transferring the pollen from the male flower to the female flower, often done with a small artist’s paintbrush.  Female flowers can easily be distinguished from the males by the presence of a miniature fruit at the base of the flower. 

    Sometimes gardeners are concerned because none of the first blooms produce  fruit.  This is because the first flowers produced on the plants will be male. In time, female flowers are produced.  Also remember that cucumbers, melons and squash do not cross-pollinate; a cucumber will not cross with a melon; a squash will not cross with a cucumber, etc.  But within each species, cross pollination often occurs. A zucchini squash can pollinate a crookneck squash, and a Crenshaw melon can pollinate a Casaba melon.  Planting the seeds from these crosses will produce fruit that will be different from either parent.

    Monday, October 8, 2018

    Composting Produces Good Organic Matter

    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. 

    Wednesday, September 5, 2018

    Pineapples - Easily Propagated





    Can the top of the pineapple fruit be cut off and planted in order to produce a new plant? The answer is YES! There are many variations on how to propagate pineapple. The drier the environment, the more precise the instructions need to be followed. In Hawaii, especially in high rainfall areas, propagating pineapple is relatively easy. 
      


    The simplest method is to cut off the top of the pineapple, called the crown, as you normally would do when cutting the fruit. Let the top sit in a shaded, dry area for 2-7 days. Before planting, remove the dried fruity portion and some of the lower leaves exposing  ½ -1 inch of the stem. Letting the crown sit for several days will seal the wound and make it less susceptible to rot. When planting, keep in mind that the mature plant can grow to 3-4 feet in diameter and height. Mature plants also have a tendency to fall over, thus planting several together, they will give each other support.

    Alternatively, the stem can be placed in a shallow glass of water. Be careful to place only the stem and not the leaves in the water.  After a short time, roots will form; it is then ready to be planted outside.  

    Thursday, August 16, 2018

    The Corn Earworm



    The corn earworm is one of the most destructive insect pests of corn in the world. But here in Hawaii it is not quite as destructive thanks to CTAHR (University of Hawaii College of Tropical Agriculture and Human Resources) plant breeders. Hawaii-bred corn varieties are more resistant to the earworm due to their thicker and tighter husks, thus limiting the number of larvae that can gain entry to the ear. This allows growers to simply cut off the tips of the ears to remove any damage that may have occurred.

    Most of the eggs of the corn earworm are laid on the young silks soon after the silks have emerged. Young larvae crawl down the silk to feed on the kernels, soft cobs and the silk itself.  Luckily they also eat each other, keeping populations low.

    Corn planted early in the year is not as seriously affected as is late corn because population densities increase as the season progresses. Early plantings will have minimal damage; later in the year one or two worms may appear in the tops of each ear of corn.

    Control
    To help control the pest, between plantings destroy the crop residue or haul it off to the compost bin. This eliminates places that would harbor the pest. Several natural enemies are present in Hawaii and, in general, they keep the corn earworm at tolerable levels. In most cases, control is simply a matter of cutting off damaged ends of corn at harvest.

    For those gardeners who are plagued with the corn earworm, here are some chemical recommendations from the University of California IPM program:
    • Spinosad -  must be applied on silks within 3 days after first silks appear and at 3-day intervals until silks turn brown.
    • Bacillus thuringiensis (Bt) - may be dusted on silks every 3 days after 5 to 10% silk formation for partial control.
    • Applying a few drops of mineral oil with a medicine dropper to silks just inside each ear 3 to 5 days after silks first appear may be effective.

    Monday, August 6, 2018

    Bananas – A Fruit for All Reasons



    There truly seems to be ample evidence that bananas are more than just a good source of potassium. Nutrients such as vitamin A, vitamin C, vitamin B6 and niacin, as well as the minerals phosphorous, calcium, magnesium and manganese are all present in bananas.

    In addition, no fruit is higher in energy value except the avocado. This is because the banana has three natural sugars -sucrose, fructose and glucose which give a substantial boost of energy.

    Other benefits of bananas are as follows:
    •         Help fight depression. They contain tryptophan, which converts into serotonin, a chemical known to make you relax and improve your mood. For this reason, bananas can also help sufferers of Seasonal Affective Disorder (SAD).
    •         High in iron. Bananas can stimulate the production of hemoglobin in  the blood and so helps in cases of anemia.
    •         Reduces the risk of high blood pressure and stroke. Bananas are extremely high in potassium yet low in salt. The US Food and Drug Administration allows the banana industry to make official claims for the fruit's ability to reduce the risk of blood pressure and stroke.  According to research in “The New England Journal of Medicine”, eating bananas as part of a regular diet can cut the risk of death by strokes by as much as 40%.
    •         Research has shown that the fruit can assist learning by making pupils more alert.
    •         Bananas have a natural antacid effect in the body so if you suffer from heartburn, eat a banana for soothing relief.
    •         Some people even rub mosquito bites with the inside of a banana skin to reduce swelling and irritation.
    •         Bananas can also help people who try to give up smoking. It seems the B vitamins, along with potassium and magnesium found in bananas help the body recover from the effects of nicotine withdrawal.

    Monday, July 23, 2018

    Hibiscus Mite

    Bumpy, wart- like growths on hibiscus leaves

    This unsightly growth is caused by the feeding of a tiny mite, invisible to the naked eye, called the hibiscus erineum mite.  It has been in the Hawaiian Islands since 1989 and is carried from place to place by wind, birds and insects.

    The mite is difficult to eradicate, and even when it is gone, it will likely return.  Biological control is the best long-term solution.  Soon after the mite becomes established, a predatory mite will most likely move in and begin feeding of the erineum mite. 

    Since the predatory mite will only reduce the pest population and not eliminate it, there will continue to be some damage. If not satisfied with biological control, using a chemical spray would be the next step:  1) prune to eliminate the worst damage, 2) spray with a registered miticide; wettable sulfur.  3) Apply 2-3 times, at weekly intervals, paying special attention to spraying the undersides of the leaves.  In addition to killing the mites, the spray will protect the new growth from further infestation so gradually the shrub will begin to recover. 

    Unfortunately, a miticide application will also kill the predatory mites, so it is either biological control or chemical.  If you see tiny, fast moving mites on the leaves, these are the predatory mites. You may want to give them a chance before pesticide applications.

    Research conducted at CTAHR’s Kahului Experimental Station (Maui) indicates that some hibiscus varieties are more susceptible to this mite than others.   The more susceptible varieties are:  Chinese Red, Herman Shierman, Orange Hibiscus, Nii Yellow and Kardinal.  Those varieties that show a lesser susceptibility to the mite are: Itsy Bitsy Peach, Monch, Zahm, Apple blossom, Apricot, Empire and Pink hibiscus.  


    Saturday, June 23, 2018

    Tropical Favorites


    Some favorite tropical fruits, spices and flowers all belong to the same plant order known as the Zingiberales. They include banana, ginger, cardamom, turmeric and the beautiful heliconia flowers.

    Banana, sometimes referred to as a tree or palm, is actually an herbaceous plant since the trunk or stems do not contain lignin. Lignin is the substance that makes wood, woody.  

    Ginger originates from Southeast Asia and is unknown in the wild but has been cultivated since ancient times. Ginger was introduced into Europe from China and introduced into Mexico and the Caribbean by the Spaniards. Today it is widely used in local medicines in India and the Far East. China and India are the largest producers of ginger.   

    Cardamom is native to India. The dried fruits are used in medicine and as a spice.  Cardamom seeds, which have a pleasant aroma, are used in curries and breads.   

    Turmeric, or olena as it is called in the Hawaiian language, comes from the root of Curcuma domestica; it is an important ingredient in curry powders.  Turmeric has been gaining recognition as an anti-inflammatory herbal remedy. Preliminary findings suggest that a chemical found in turmeric called curcumin may have carcinogenic retarding properties but these findings have not been confirmed. With its bright yellow color, turmeric is also used as a fabric dye. This species is unknown in the wild; it is sterile and does not produce fruit. Turmeric is also known as Indian saffron. 


    Lastly, in the plant order Zingiberales there are over 100 different species of heliconia flowers.  They produce some of the most beautiful and commercially important flowers for both potted plants and bouquets. Heliconias require high temperatures, humidity and light intensity.  In the wild they grow mainly in forest clearings. The Bird of Paradise, which is the national flower of South Africa, is also in this group. 

    Wednesday, May 16, 2018

    Edible Ornamental Plants



    In frontier times, people foraged the  nearby hills and fields for edible plants. Since the early 1900’s, however, Americans began the great migration to the cities and  eventually lost their foraging ability. Perhaps the time has now come to learn which ornamental plants and common weeds can be a  good source of nutritious food.

    Here is a short list of some well-known edibles. Many university websites have a more comprehensive list of ornamental edibles.

    A. Weeds - If you can’t beat them, eat them!
     1. Dandelions, Taraxacum officinale -Fresh dandelion leaves can be eaten raw, in salads, added to a stir fry, or boiled and steamed like spinach. They have a bitter taste, but boiling will help take that out. Dandelions also make a great addition to soups and stew. They are high in carotenes, iron, calcium and vitamins A and C. As a detoxifying agent, dandelions aid with liver, urinary and gall bladder disorders, diabetes and high blood pressure. Dandelion root tea is sold in local health food stores. 

    2. Lamb’s quarters (Chenopodium album) is also called wild spinach with similar nutritional value to spinach. 

    3. Burdock (Arctium Lappa) is a weed rich in potassium, iron and calcium. 

    4. Common mallow (Malva neglecta) the leaves, stems, and immature seeds are eaten raw or cooked. Mallow is reported to be rich in calcium, magnesium, potassium, iron, selenium, and vitamins A and C.

     5. Purslane (Portulaca oleracea) is a succulent; the leaves, stems and flowers can be eaten either fresh or cooked. The leaves contain more omega-3 fatty acids than any other leafy vegetable plant.
    Other edible weeds include chickweed, white and red clovers and plantain.

    B. Edible Flowers
    1. Marigolds are one of the most commonly grown ornamental annuals. When dried and crumbled, the petals of marigolds can substitute for the most expensive spice in the world: saffron. 

    2. Roses, both the petals and the rosehips (fruit), are edible. Rose water is often used in scones, cakes, sherbets, salads and icings.  

     3. Sunflowers – in addition to the commonly eaten seeds, the petals can be added to soups and stir-fry dishes. The sunflower buds can be steamed and eaten like an artichoke.

    4. Daylilies (Hemerocallis sp.) - Some species (especially H. fulva) are cultivated in Asia for their edible flowers. The petals can be eaten raw or more commonly dried and used as a flavoring in soups. The young shoots should be cooked and have a pleasant sweet flavor. Even the roots are edible.

    Nasturtium, violas, borage and calendula flowers are also edible and frequently used in salads.  Bon Appetit! 

    Caution: Before collecting, research the plant to verify it is edible, and more importantly, make sure it is properly identified. Eating the wrong plant can be disastrous.