Fruitless Attempts in the Garden

Spending lots of time and money in the garden with no results?  One solution is to build raised beds, and in some instances, this may be the best approach. But before building an expensive raised bed, a little investigation and a few changes may produce the desired bountiful garden.

First, efforts need to be directed toward modifying the soil.  Here are some important considerations: 1. The pH could be too low for good growth, a common occurrence in Hawaii. In this case, an application of lime will rectify the situation.  If the pH is too high, common in many areas, sulfur or sulfur products would be advisable. 

 2. Soil nutrient levels may be deficient; common elements that may be lacking include nitrogen, potassium, phosphorous, calcium and magnesium.  These can be corrected with the addition of the proper fertilizer. Both pH imbalances and nutrient deficiencies can and should be diagnosed with a soil analysis. 

3. The soil may be contaminated by plant pathogenic fungi. In this situation, planting resistant varieties to the disease is most important. Crop rotation is another approach. See the article, "Replanted Vegetables Continue to Die" at this website.

  

Additional inquiries should include learning the proper planting dates.  Failures in the garden are occasionally caused by planting cool season vegetables such as lettuce, broccoli and cabbage in the summer, or warm season crops such as peppers and tomatoes in the winter. Moreover, the wrong varieties are often planted. Reading the publications available on the CTAHR website, http://www.ctahr.hawaii.edu/site/info.aspx, will reveal which varieties do well in Hawaii. In other areas, check the local University Cooperative Extension offices or website.

These are a handful of factors that may assist you in developing a green thumb and a lush garden.  Don’t give up! First obtain a soil analysis, then educate yourself: read about the plants you want to grow. Take gardening classes. Use the CTAHR and other Extension websites along with www.gardenguyhawaii.com 

Miconia "Sound the Alarm!"

                                                  Clearing Miconia stand in Tahiti

Miconia calvescens, is a tree from 35 to 50 feet tall with large leaves up to 3 feet in length. Although attractive with its beautiful leaves, green on top and purple on the bottom foliage, it is perhaps the most invasive and damaging, alien plant species to the wet forest lands of the Pacific Islands. These trees will form a large, thick canopy which can produce 100% shade, killing out or inhibiting the growth of all native species below. Miconia plants are a threat to completely take over moist and wet forests.

Miconia was introduced to Hawaii as an ornamental in the 1960s and now poses a threat to completely take over forests receiving 75-80 inches or more of annual rainfall. If left uncontrolled, it is estimated that miconia could invade up to 121,000 acres on Oahu. On Maui 37,000 acres could potentially contain miconia.  Presently, the Big Island has large infestations on the windward side, particularly on the Hamakua Coast and smaller populations on the leeward side.

A single mature tree has the potential of producing 3 million seeds, two or three times a year. These seeds can remain viable in the soil for 10 years or more. The seeds are spread by man, through the mud on his boots and other equipment including bulldozers. Seed is also dispersal by birds; in Hawaii, dispersal is presumably by the Japanese white-eye, the common mynah and perhaps the northern cardinal. In trials in Tahiti, a square yard of the top 2 cm. of soil from a dense Miconia stand, produced over 17,000 miconia seedlings in six months.

Miconia was introduced to Tahiti in 1937 and has since destroyed nearly 70% of the native forests and is directly responsible for threatening 25% of their native forest species with extinction. Miconia also causes serious landslides due to its shallow root system.

Hawaii residents: For many years the Big Island Invasive Species Committee (BIISC) has worked to maintain a miconia-free buffer zone and to stop miconia from spreading to upper-elevation, pristine watershed forests. Funding is now inadequate to continue this focus. For more information, you may contact them at (808) 430-3090 or email at pageeles@hawaii.edu.

Today, the strategy for control is to implement a serious of biological control measures: to introduce natural enemies from Miconia’s origin in Brazil. The approach is to use a variety of agents including weevils which bore out the stems, caterpillars which feed on the leaves, and other larvae which feed on flowers and seeds. The list of biological control agents also includes a fungus which attacks the leaves and causing premature leaf drop.  

See the invasive species website at http://www.hawaiiinvasivespecies.org/pests/miconia.html for more information.

Gold Dust Day Gecko

The Gold Dust Day Gecko, a native to Madagascar, sometimes referred to as the Madagascar Day Gecko, does well in a tropical climate. Unlike most geckos, it is a diurnal animal, active during the day. They are territorial animals; males are especially aggressive towards other males.

These geckos are very colorful, usually bright green or a yellowish green. Halfway down their backs, they have three red teardrop markings. A blue shade is present around the eyes with bright gold markings on the back and neck. They feed on various insects and other invertebrates and are capable of eating other smaller lizards. They also eat soft, sweet fruit as well as pollen and nectar from flowers.  But they don’t bite humans.

Although these geckos will come into the house, probably looking for food, they are an arboreal species, spending most of their time in trees. If exclusion is desired, treat them as you would mice, rats and cockroaches; make sure to screen all windows, doors, ventilation passages and any small openings into the house.

Another species of gecko is the House Gecko, residing with humans in homes rather than in the wilderness. Being aggressive, this pale brown gecko drives other species away from the house. They are primarily nocturnal.

There are over 900 species of geckos worldwide, but only seven or eight reside in Hawai`i. Geckos are the only lizards who are able to make sounds, other than hissing.  Feeding on cockroaches, mosquitoes, ants, termites and moths, geckos are beneficial to home owners.

It has been thought that geckos are able to run up and down walls and ceilings due to tiny suction cups on their toe pads. However, recently scientists found that geckos have a network of tiny hairs and pads on their feet. With millions of hairs on each foot, the combined attraction of the weak electrical forces allow the gecko to stick to virtually any surface, even polished glass.

Seed Germination - Nothing's coming up!

Planting a vegetable garden has a variety of challenges. But how disappointing when the seeds are planted and nothing comes up! Here are primary reasons for poor seed germination.

 1. Planting depth – small seeded vegetables like carrots and onions can easily be planted too deep. If planted too close to the surface, the seed can easily be washed away during heavy rains. Consult the seed packet for proper planting depths. 

2. Temperature – some seed need the soil temperature to warm up before they will adequately germinate, while other cool season vegetables like onions, germinate best in a cool soil. 

 3. Water -  too little and seeds will not germinate or will dry up after germination. With too much water, seeds and seedlings can die from lack of oxygen or be overcome by fungi. Even under normal moisture conditions, different species of fungi and bacteria can cause seeds to rot.  Seeds and seedlings should always be kept moist, but the soil should not remain soaking wet.  

 4. Soil pH - each vegetable seed as well as other plants will have its range in which it will germinate best. 

5. Herbicide residues -  may still be active in the soils causing poor germination.  A high fertilizer content in the soil could also hamper germination. 

6.  Insects will often feed on  seeds and young seedlings.

7. And finally, the seed itself! Poor seed germination can particularly be a problem in humid climates.  Relative humidity influences the moisture content of the seed. The higher the moisture content, the lower the germination rate will be, especially, after one year.

As a general rule, vegetable and flower seeds can be kept for one year without appreciable decrease in germination. Storage, however, may be extended to 10 or more years under proper conditions; seed moisture and temperature are the most important factors. The drier the seeds, the longer they will store.

In humid climates such as Hawaii, storing vegetable seeds in a dry, sealed glass container should keep most seeds viable for a year. For longer storage, place seeds in a moisture-proof container and store in the refrigerator.

Longevity of vegetable seeds will also vary depending on the species.  For example, collards, cucumber, endive, radish and water cress produce some of the hard seeds, rated as lasting 5 years. Next come beets, cabbage, cauliflower, eggplant, kale, mustard, squash, swiss chard, tomato, turnip, watermelon, rated at a 4 year longevity; asparagus, beans,  carrot,  celery,  chinese cabbage, New Zealand spinach, pea, and spinach, at 3 years; leek,  sweet corn, okra and pepper are rated at 2 years; and finally, the last group is rated at a mere 1 year longevity - lettuce, parsley, parsnip and onion.

Photo: Purdue University

Hummingbirds and Pollination

 

About 25% of plants are wind pollinated. The rest rely on pollinators: bees, bats, beetles, butterflies and yes, hummingbirds, as well as some other birds. During the day hummingbirds feed about every 10 minutes and consume up to 2/3 of their body weight from the nectar of plants; they can service 20 flowers per minute. The wings of hummingbirds beat up to 55 beats per second and allow these tiny birds to fly at speeds up to 50 mph. They can hover and even fly backwards or upside down. 

Hummingbirds are primarily attracted to tubular flowers. They are stimulated by color, especially the color red. Clumps of bright red, orange and pink flowers are more visible to them than other colors. Plants with red, tubular shaped flowers are an excellent choice in the garden to attract hummingbirds. Other plants that attract these birds are gladiolus, honeysuckle, iris, lupine, nasturtium, petunia, and cosmos. 

Recently, I was asked if hummingbirds pollinate vegetables. I am having difficulty finding specific vegetables that they pollinate. That’s probably because there are not many vegetables with red, tubular shaped flowers, which attract the hummingbirds.  

Lastly, the Islands of Hawaii have no hummingbirds, but a one inch moth is often mistaken for this tiny pollinator. The hummingbird moth has grey beating wings with a quiet humming sound. Unlike like other moths, this fellow is diurnal and uses his long proboscis to ingest nectar from plants and flowers.  Hawaii's hummingbird moth is also a pollinator! 

Photo: University of Maine

Plant a Rainbow of Colors in Your Garden

When planting a vegetable garden, let color be your guide to healthy eating.  For a number of years, scientists have been discovering the health benefits of the color pigments in food.  For some gardeners, a vegetable garden is lettuce, collard, mustard greens and kale- all healthy, leafy green vegetables.   But for health sake, add some color such as red tomatoes, yellow squash and purple eggplant.  Grow a rainbow of colors to the garden for good health.

Red colored fruits and vegetables contain natural plant pigments called lycopenes or anthocyanins. These compounds may help reduce the risk of several types of cancer, especially prostate cancer. By the way, the lycopenes in cooked tomatoes with a small amount of fat are absorbed better than lycopene from raw tomatoes.  Sun dried tomatoes are reported to have twelve times the lycopenes as raw ones. So plant plenty of tomatoes, beets, watermelon and red peppers. If there is room in the garden, include a pigmented citrus tree like pink grapefruit. 

Orange and yellow colors come from natural plant pigments called carotenoids.  Beta-carotene is converted to vitamin A which helps maintain healthy eyes.  Carotenoid-rich foods can reduce the risk of cancer, heart disease and improve the immune system function.  Plant plenty of yellow sweet potatoes, squash, pumpkins and carrots.  Citrus contains hesperidin, also found in the skin of tomatoes, and naringenin, which are anti-inflammatory and antioxidant. Curcumin, found in turmeric, known in Hawaiian as olena, has antioxidant properties. Turmeric is a popular Indian spice used in curries and other dishes.  Anecdotal evidence suggests that turmeric can be used to deter ants in the garden.

Other yellow and orange fruits grown in Hawai`i are pineapples, papayas and mangos. Pineapples contain bromelain, an enzyme which aids digestion.  Papaya and tangerines contain beta-cryptoxanthin, another carotenoid, playing an important role in vision and in bone growth. Papayas can easily be grown from seeds or purchased in abundance at local markets.

 Greens are colored by a natural plant pigment called chlorophyll.  Some greens contain lutein which helps keep eyes healthy. Here is a familiar list of green vegetables: green peppers, peas, parsley, watercress, arugula, spinach and kale.  Crucifers like broccoli and cabbage contain chemicals which may help protect against some types of cancer.  Leafy greens such as spinach and broccoli are excellent sources of folate, which is a B vitamin. 

The blue and purple colored fruits and vegetables also contain pigments called anthocyanins, powerful anti-oxidants which improve brain function and help to reduce the risk of cancer, stroke and heart disease.  Fig trees grow well in tropical and sub-tropical climates and should yield delicious, healthy fruit.  Anthocyanins, also found in strawberries and raspberries, act as powerful antioxidants that protect cells from damage. 

The whites contain pigments called anthoxanthins which are shades of white or yellow.   This group consists of onions, garlic, cauliflower, turnips, mushrooms, potatoes and bananas.  At least one of the group, garlic, contains a health-promoting chemical called allicin. This compound may help lower cholesterol and blood pressure and help reduce the risk of stomach cancer and heart disease. Potatoes, as well as bananas, are good sources of potassium.