Friday, August 31, 2012

Cracked Mangoes


The cause of cracking in mangoes is the same whether it’s mangoes, oranges or tomatoes. The majority of cracks are caused by irregular periods of dry and wet weather.  Abundant rain alternating with dry spells will produce stages of slow growth followed by rapid growth, resulting in cracked fruit. 

In addition, a fungus or bacteria may invade these cracks and cause the fruit to rot.  The weather is beyond our control, but if irrigation is involved, an even supply of moisture throughout the growing season will help eliminate cracking in fruit.

Also, anthracnose fungal disease, common on mangoes, can cause deep cracking in certain varieties which are especially susceptible to this disease. The florigon mango variety is rated ‘moderately resistant to anthracnose.’


Friday, August 24, 2012

Invader in the Lawn



A small-leafed, weed with purple flowers is spreading over my lawn. It has nasty stickers and a long tap root.  Sensitive plant is one name of this weed; sleeping (or sleepy) grass is another.  The name comes from the fact that the leaves close when they are touched. In Hawaiian it is called pua hilahila.

This invader commonly grows in well drained soils that have been disturbed such as lawns, orchards, pastures and roadsides.  It does not grow under forest canopies.  It is a real scourge as it crowds out other plants and grows up into taller ones.  It appears from sea level to about 4,000 ft. in elevation. The sensitive plant can also be a fire hazard in dry terrain. 

Control
Physical:  Hand weeding is obviously difficult due to thorns and a strong, woody root.  In pasture land, it can be controlled by intensive grazing where cattle will kick the pua hilahila out of the way to get at the grass beneath. 

Chemical: The sensitive plant can be controlled with the herbicides Roundup and Garlon. Roundup will also damage or kill your lawn. In lawns, herbicides containing the active ingredient 2,4D (Crossbow, Trimec Southern) are fairly effective and should not damage the lawn.  Damage can occur to carpetgrass when Trimec Southern is applied. Locally it has been observed that no damage occurs when applying Garlon to many of our lawns. When in doubt, spray a small portion of the lawn and wait for 2 weeks to see if any damage occurs.  If plants are disturbed before spraying, the leaves will fold up and the herbicide will be ineffective. For further information go to the following website: http://www.ctahr.hawaii.edu/invweed/WeedsHI/W_Mimosa_pudica.pdf

Tuesday, August 21, 2012

The Citrus Tree Switch : Sweet to Sour


 Have you ever purchased an orange tree, harvested sweet oranges for many years, only to have a crop of sour fruit the next? 

All commercially sold citrus trees are budded. A budded tree is like a grafted tree, except a single bud is used instead of a graft which is a few inches of stem containing several buds.  When you look at the trunk of a citrus tree, you should be able to observe a slight to obvious bulge. This is where the original budding took place; it is called the bud-union. Everything above that bulge or bud-union grew from that bud and is the variety of tree you purchased; everything below is of the original rootstock seedling.

Sometimes shoots originating from below the bud-union will grow up into the tree. These are typically covered with large thorns. If the shoots not pruned out, they will continue to grow, branch and eventually form a good part of the tree. Rootstock branches are usually more vigorous and will eventually blossom and produce fruit. This fruit is different from the variety you originally purchased, and most often is quite sour. These branches must be cut out so the original budded variety can repopulate the tree and produce sweet fruit.

Tuesday, August 14, 2012

What is Chinese Spinach?


Chinese spinach is not what we consider true spinach but is actually known as an amaranth; that is, plants that come from the genus amaranthus. Although several species in this group are considered weeds, others are used as high-protein grains, leafy vegetables or valued as ornamentals. It is an ancient crop originating in the Americas, with inflorescences and foliage ranging from purple and red to gold.

The amaranth that is known as Chinese spinach is grown for its tender leaves. Depending on the variety, this plant can vary in foliage color, leaf shape, plant height and flavor. The plants grow well in hot weather, preferring a sunny location with plenty of moisture.  Don’t worry about planting too densely; once the seedlings are up and growing, the young plants can be thinned to six inches apart. The plants that have been thinned are edible! When established, the growing tips can be pinch to force the plant to branch and make more new, tender growth.  The tender young leaves and stems are cooked like spinach or used for stir-fry and soup. They are quite high in protein. Chinese Spinach is also known as Calaloo, Hon-toi-moi, Tampala, or hin choy. 

Chinese spinach seeds can be ordered from various seed companies.  When buying the seed from a catalog, look for entries under Amaranthus and make sure "edible for greens" is stated.  As mentioned above, some varieties of amaranthus are grown for grain while others for the leafy greens.

Tuesday, August 7, 2012

Ivory Nut Palm



Part of the immature seed of the ivory nut palm is pulpy and sweet and is used as food for both people and animals. The mature, dry seeds however, become so hard that it requires a hacksaw to cut one in half. They are known as vegetable ivory and are a sustainable, alternative to animal ivory.  Many beautiful carvings have been produced from these seeds.

During Victorian times, thimbles, dice and jewelry were manufactured from this substance. Before plastic buttons became popular, it was a key material in the button industry. During the 1920′s, 20% of all buttons made in the United States were made out of the seed of the ivory nut palm. If you have never seen the beautiful carvings made from these seeds, check out a web site like http://waynesword.palomar.edu/pljan99.htm

Germinating seeds of the ivory nut palm is difficult. Therefore, plant as many as possible since not all will germinate.  Ones that do germinate, may take several months or even up to a year.  If possible, allow the fruit to fall, do not pick it from the tree.

One method of germination is to plant the seed, anywhere from half buried to just under the soil, in a sterile, well-drained planting media. Keep it moist but saturate log the soil. Some horticulturalists insist that removing the seed coat from around the seed is important while others have been successful without removing it.

 Since the seeds take a long time to sprout, there is always the danger of insects and fungi destroying the seed. Yet as long as the seed has not turned to mush, there is still hope for germination.   The seed will send down roots before it sends up a sprout.  Once germinated, the problems are not over.  A number of people have been successful in germinating the seed only to have it die from an unknown cause shortly thereafter.

The second approach to germinating the seed is to mimic nature.  As the seed lies on the ground, there are hundreds of different types of fungi, bacteria and other microorganisms growing on and around that seed. The exact role of these organisms is uncertain, but it is possible that the gases and other chemicals that they produce may trigger and aid in the germination of the seed. That is why some recommend placing the seed in a plastic bag with organic matter (OM) and allow the OM to decompose. Leave the seed in the bag for a couple of weeks to a month. Then plant it in a pot with a well draining soil mix.

Friday, August 3, 2012

Don’t Pile Mulch Against Tree Trunks



Applying organic mulch to the garden provides many benefits: improves the soil structure, adds micro and macro nutrients to the soil, conserves water during a drought, and acts as a food source for many beneficial microorganisms living in the soil.

When applying mulch around trees, however, an air space must be kept between the mulch and tree trunk so the bark can dry. A constantly wet trunk will provide a suitable environment for disease. This, of course, does not apply to all trees. For instance, the magnolias of the Southern States grow along streams and swamps.  But other trees, like citrus and avocado, are susceptible to crown rot.  

 If the fungal organism is present and the bark remains wet for a prolonged period of time, infection will occur.  Untreated, the tree will die. Don’t pile mulch against the tree, and don’t position sprinklers so the water hits the trunk. Keeping the tree trunks dry as much as possible is important.

In general mulch enhances the health of trees but precautions need to be observed.