Showing posts with label vegetables. Show all posts
Showing posts with label vegetables. Show all posts

Tuesday, July 22, 2014

Planting Carrot Seeds

Carrots seeds are small and slow to germinate, and the seedlings are fragile. Because of this, problems can arise. 

1) When heavy rains occur, the seeds can easily wash away. Placing some type of cover over the seed bed will help, but it is needed only until the seeds have emerged.

2) Few seedlings will be able to emerge through a crusty soil. Careful soil preparation is important.

3) Follow proper planting directions: 

    a) plant carrot seeds 1/4 inch deep in heavy soils, and 1/2 inch deep in light soils. 

    b) Thin out dense seedlings carefully in order to give roots enough room to expand normally. Space plants 2 to 4 inches apart.

    c) Make sure to check the date on the seed packet to be certain the seeds are current.  

Monday, April 28, 2014

Cilantro.... or is it Coriander?

Cilantro is a cool season plant. It flourishes during cool nights and moderate, sunny days as in the spring and fall. But it will bolt at the first sign of hot weather. In tropical regions like the islands of Hawaii, cooler, mountainous areas would perhaps give cilantro the longest season, provided there is adequate sunshine. Cilantro, however, is a true annual and even under the best conditions, it will send up flowers and eventually die within the year.  In order to minimize the bolting effect, cilantro should not be grown during the warmer, summer months. The best time for planting would be after the summer heat from September or October until perhaps March.

Bolting is the premature flower formation initiated by hormones within the plant system in response to high temperatures, as well as drought and starvation.  This unwelcome occurrence in leafy vegetables such as cabbage, lettuce and cilantro,  takes the plant out of its leaf producing mode and switches over to flower and seed production. In many regions, it is a common occurrence with cilantro.
There are some slow-bolting varieties, Calypso is one, that can extend cilantro’s productivity perhaps a month. Snipping off the first newly emerging flower buds may also extend the leafy period, but only slightly.

Most cooks are familiar with the seasoning called coriander. Coriander is actually the small, dried fruit, often referred to as the seeds of the cilantro plant. In fact, the scientific name for cilantro is coriandrum sativum, or coriander, also known as Chinese parsley. All parts of the plant are edible. The fresh leaves and the small dried fruit are the parts most traditionally used in cooking.

                                                      seed capsules
The fresh leaves are often used in South Asian and Chinese cooking as well as in Mexican cooking, particularly in salsa and guacamole.  Since heat will diminish the flavor, leaves are frequently used raw or added just before serving. They will lose their aroma when dried or frozen.

Coriander seed is a main ingredient in garam masala, an Indian spice, and in curries. Although the ingredients in garam masala can vary, it commonly includes coriander, black pepper, cumin, cardamom and cinnamon.  In India, roasted coriander seeds, called dhana dal, are eaten as a snack.

Coriander is used for pickling vegetables and for making sausages in Germany and South Africa. In Russia and Central Europe, the seeds are used as an alternative to caraway seeds. Even in brewing certain types of beer, particularly some Belgian wheat beers, coriander is an added flavor.

Like many plants, coriander may contain properties useful in the treatment of Type 2 diabetes and high cholesterol.  Research is presently investigating these claims and other medicinal attributes of coriander.  

Photos by Forest and Kim Starr

Monday, April 7, 2014

Stink Bug

 A wide range of fruit and vegetables, as well as leaves and flowers, are susceptible to the Southern Green Stink bug, nezara viridula. In some countries it is called the green vegetable bug.  

Damage is achieved by inserting their needle-like mouth part into the plant tissue and sucking out the plant juices. Some stink bugs can cause wart-like growths as the plant reacts to the piercing. Although the green color of the pests blends with the foliage making them difficult to find, bugs can be visible feeding in the garden on beans, cabbage, peppers, tomatoes, okra or in the trees on such fruit as mangoes and macadamia nuts. The adults are active fliers, and when disturbed, will fly away or fall towards the ground.

Control is sometimes difficult. Horticultural oils, including Neem oil, work well, but the solution needs to contact the insect. (Read more about Neem on this website.) To spray when the insect is not there will do no good. Oil, as well as soap, is a contact insecticide. Harsher chemicals like Sevin and Orthene will also control this pest. Yet in many areas biological control is effective, and chemical control is seldom necessary. 

In Hawaii, introduced parasites (good guys) are well established and are generally effective. Predators include spiders and the big headed ant. The ants prey upon the eggs and immature stages of the stink bug, taking them back to their nests. The stink bug is so named because of the strong odor emitted from scent glands when disturbed. 

Monday, December 16, 2013

Onion Thrips

As a common problem in the vegetable, onion thrips is a major insect pest not only of onions and leeks but also attacks broccoli, cabbage, carrots, cucumbers, garlic, melons, papaya, pineapple, squash and tomato. (Note - thrips refers to one or many.) 

The damage from the feeding results in whitish or silvery streaking on the leaves. Black droppings from the insect may also be seen. Thrips populations are often greater in the warmer months of the year.

There are predators and parasites that attack the thrips but often are not effective for proper control. Sometimes washing with a stream of water will help. Plants, of course, will tolerate a certain level of infestation causing only cosmetic damage. If injury threatens crops loss, then treatment is called for. Synthectic pyrethroid insecticides such as Warrior (lambdacyhalothrin) and Ammo (cypermethrin) are effective in controlling onion thrips.

Bulb Onion Production in Hawaii by R.Hamasaki and H. Valenzuela is a publication available on the CTAHR website.

Monday, November 25, 2013

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.

Monday, November 4, 2013

Bolting in Vegetables

Bolting is the process of premature flower formation in response to high temperatures, as well as drought and starvation.  This unwelcome occurrence in leafy plants such as broccoli, cabbage, lettuce, and spinach,  takes the plant out of its leaf producing mode and switches over to flower and seed production.

Many vegetables are divided into two groups: cool season and warm season vegetables. Although in Hawaii seasons may vary little in temperature and many vegetables can be grown year around, some will do better when planted within the given time frame. 

Broccoli and lettuce are cool season vegetables. As long as the temperatures remain cool, the lettuce will continue to produce tender leaves, and the broccoli flower buds will remain closed. Generally lettuce and broccoli are planted from September through March/April.  During the hot summer months plants can bolt.  At higher elevations, cool season vegetables such as lettuce, beets, broccoli, cauliflower, chard, kale, peas, turnips and mustard, may be successful planted in late spring and summer.   

Warm season vegetables include tomatoes, cucumbers, melons, squash, peppers, corn and eggplant.

Monday, September 16, 2013

Perils of Growing Zucchini

For some gardeners, growing zucchini  is an effortless task, the end result being zucchini bread, zucchini cake, zucchini pancakes, zucchini salad,  baked zucchini, broiled zucchini, fried zucchini, etc., etc. Having lived in California, I know this to be true.  Living in the tropics, on the other hand, is a different story. Here is mine:

My first attempt at growing zucchini squash failed because a bird or rat stole the seed. Then I planted the seeds in small containers and placed them in a netted area waiting to be transplanted. On my second attempt, the plants grew well but finally died, succumbing to the powdery mildew (PM) fungus. Next, I planted PM resistant varieties. This helped, but I still needed to use fungicidal sprays such as horticultural oil, Serenade and/or baking soda. See this website for more information on powdery mildew. This points out that the word ‘resistant’ means just that; it doesn't mean immune! It could also mean that in tests, the resistant variety simply did ‘better’ than nonresistant varieties.

Well, the bird or rat problem seemed resolved; the PM problem was addressed, more or less, and a new crop was growing well. The plants were blooming, and small fruit developing on the plant, but then they dropped off. This was an attack of the pickleworm! So I threw some ¾ inch bird netting over the plants. This will keep most of the pickleworm moths out but allowed bees to come in and pollinate.

When the zucchini was nearly ripe, I observed that the whole plant was dying with what appeared to be a virus, one of several that attack squash: squash mosaic virus SMV, cucumber mosaic virus CMV and watermelon mosaic virus WMV. These different viruses are transmitted by insects which feed on virus-infected squash plants or some nearby weeds. Once the plants are infected, there is nothing that can be done. The virus  will eventually kill the plant. Symptoms include distortion of the leaves, chlorotic (yellow) mottling and a dark green mosaic pattern. Infected fruit coming from such plants show a strong mottled pattern. The best preventive measures include insect control along with host weed management.

Note: Squash, along with melons and cucumbers (cucurbits) are unique vegetable plants that 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.  Insects do the major pollination work.  Female flowers can easily be distinguished from the male by the presence of a miniature fruit at the base of the flower. 

Sometimes gardeners are concerned because none of the first blooms produce any fruit.  This is because the first flowers produced on the plants will be male and cannot give forth fruit. In time female flowers, and subsequent fruit, will be produced.

Unfortunately,  zucchini is one vegetable I will not be planting in the future. 

Monday, September 2, 2013

Too Much Rain & More about Corn

 Some areas of the world receive plenty of rainfall.  When there’s too much rain, the following ill-effects on plants may be observed.

1.  A general yellowing.   a.) This can be due to the soil remaining wet for a long period of time thus excluding soil oxygen. In this anaerobic condition, plants will yellow. b) Likewise, the profusion of rain is washing the soil nitrogen below the root zone, and plants become nitrogen deficient, causing yellowing.

2. More fungal leafspot diseases (most notably tomatoes ). Disease causing spores land on the surface of a leaf, germinate and infect the leaf. In a short time thousands of spores are produced. When a rain droplet or water from irrigation lands on the leaf, these newly produced spores will be splattered to other areas of the leaf and to nearby leaves. They in turn germinate and infect these new areas. Thus, more rain, more splashing, more spreading of the spores and more disease.

3. Problems with corn. 
 If the abundance of rain occurs during corn pollination, the ears of corn may lack a full complement of kernels. This is due to a lack of pollination because  the wind-born pollen is washed away. Low pollination is also caused by improper planting densities. Do not plant one or a few individual seedlings, or even a single row. Plant a minimum of 4 rows, 8ft long.  For more on growing corn:  search corn in the blog search

Tips for Picking Corn
·        Mark the calendar the day the corn was planted. In Hawaii, sweet corn is harvested 7O-85 days after planting.
·        Corn is ready when the silks begin drying and turning brown.
·        Record the date at which half of the plants show the silks emerging from the new ears. Under warm summer conditions, the corn will be ready about 18 days later.

·        Perhaps the easiest clue is to pull the green husk back from the cob and check the appearance of the corn kernels. If the corn looks ready, it’s time to pick.  

Monday, July 8, 2013

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. 

Monday, June 24, 2013

Transplants vs. Direct Seeding

Should gardeners plant vegetable seeds directly into the ground or plant them in small pots first, then transplant them into the garden?  
Some vegetables need to be direct seeded, while others are best transplanted. But most vegetable plants do well either way.

In general, transplants are easier to care for.  They are usually started in a more controlled environment - a greenhouse or some type of sheltered area.  Here, the seedlings are better protected from soil diseases, especially when a sterile potting mix and clean pots are used. A greenhouse offers protection from insects, animals digging up the ground and environmental stresses like hot winds and cold temperatures.  In cooler areas, seeds can start in a warm  environment and later be transplanted outdoors. 

Yet from time to time transplanted vegetables suffer from transplant shock. When the seedlings are set into the ground, the roots are damaged in the process. Plant growth is delayed until the roots recover. 

Certain plants can regenerate new roots quickly and as a result transplant easily; they include broccoli, brussel sprouts, cabbage, lettuce and tomatoes. On the other hand, cauliflower, celery, eggplant, onion and peppers are slower to regenerate, but they can still be successfully transplanted. The cucurbits (cucumbers, melons, squash, etc.), legumes (beans and peas) and corn have even slower root redevelopment, but if root disturbance is kept at a minimum, they will do fine. 

Vegetables that have a taproot like beets, carrots and turnips should be direct seeded.  Transplanting these vegetables will cause deformations and undesirable lateral root development. 

Monday, June 10, 2013

The Difficulties of Growing Spinach

For many gardeners, it’s a matter of throwing the spinach seed on the ground and later harvesting a plentiful crop. Yet others struggle; here are a few reasons why:

1. When growing spinach, knowing the soil pH is important. Spinach is sensitive to highly acid soils. The soil pH (acidity/alkalinity) should range from 6.4 to 6.8.  When the pH drops too low, the following symptoms can occur:  low germination, yellowing, slow growth, browning of the margins and tips of seedling leaves and even death of the plant. If the pH is too high, leaves may have a general yellowing (chlorosis).

 A pH of 7 is neutral, above is alkaline and below 7 is acidic. A soil analysis will reveal the pH.  If needed, adding lime will slowly raise the pH of the soil.  If a soil is alkaline, sulfur is added to lower the pH.

2. Most spinach varieties are susceptible to cucumber mosaic virus (CMV).  Symptoms include a slight chlorosis of younger leaves along with narrow or "puckered" young leaves. Leaves also can have an inward rolling of margins. In advanced stages of the disease, the plants often appear stunted. Melody F1 and Savoy hybrid 612F are reported to be resistant to CMV.

3. Spinach is a cool-season vegetable and belongs to the goosefoot family (Chenopodiaceae) along with beets and Swiss chard.  They thrive best during the cool, moist seasons of the year. During periods of warm weather and long days, the spinach plant will bolt - stop its leafy growth in favor of flower and seed production. The Tyee variety is one variety that is slow to bolt.

4. And lastly, it is important to use new, fresh seed each year. Spinach seed that is more than a year old, rarely germinates over 80%; the germination rate diminishes with each year. Beet seed will germinate in temperatures as low as 380F, but good germination for spinach is between 50 and 60 0F. High soil temperatures result in reduced germination. Spinach is a cold-hardy crop and can withstand temperatures as low as
20 0F.

Spinach can be grown successfully on a variety of soils, but a fertile sandy loam high in organic matter is preferred.

Ask the Garden Guy Science Based Answers to Garden Questions, is an excellent resource book for the gardener. Some popular topics include Slugs and Snails, Organic Pesticides, Reasons, Why Vegetable Seeds Do Not Germinate, What’s So Hot about Manure? and Mushrooms in the Lawn.  Purchase by clicking on the image of the book above.

Monday, June 3, 2013

Growing Corn in the Tropics

In Hawaii, as well as other tropical areas of the world, corn can be planted year round. This will give gardeners three and possibly four crops a year.  

A major complaint from backyard  growers, however, is that the individual ears of corn produce few kernels.  Poor pollination is the most common cause.  Since corn is wind pollinated, it needs to be densely planted in order to achieve good pollination. Planting a compact square or a dense circle will ensure better pollination than a few plants or long rows. The best recommendation is to plant a minimum of 4 rows about 8 feet long rather than 1 or 2 long rows. 

Weather patterns can adversely affect the corn crop.  Too much wind or heavy rains during the pollination period, or very dry weather will impede pollination. In addition, from pollination to harvest, corn plants need adequate water to insure full kernel development.

Corn varieties are classified into two groups, tropical and temperate. The tropical supersweet corns are bred in Hawaii.  Popular ones include Supersweet #9 and #10.  If residing in the tropics, growers should be aware that many seed company catalogs list only the temperate hybrids: Bantam, Golden Cross and Jubilee.  Some of these seed packets are also found in local stores.  These temperate varieties have, in general, been very disappointing when grown in Hawaii and presumably in other tropical regions.

Ask the Garden Guy Science Based Answers to Garden Questions, is an excellent resource book for the gardener. Some popular topics include Slugs and Snails, Organic Pesticides, Reasons, Why Vegetable Seeds Do Not Germinate, What’s So Hot about Manure? and Mushrooms in the Lawn.  Purchase by clicking on the image of the book above.

Monday, May 13, 2013

Stunted Pepper Plants

The  pepper plants are stunted, and the leaves are crinkled, what’s the problem?

There are a number of factors that contribute to stunting: nematodes (check for knotted/galled roots), under irrigation, over irrigation and lack of fertilizer.  The crinkled leaves, however, give a clue in diagnosing the problem. The mosaic virus complex is a common disease of peppers causing green and yellow mottling, crinkling and distortion of the leaves, and stunting of the plant. There is no control for the virus itself. Since viruses are systemic, removing infected leaves or pruning out infected limbs, in the case of a tree, would not be a correct control method.

Insects such as aphids, transmit many viruses, therefore, controlling these pests would help. Removing the surrounding weeds is important since they may harbor the virus, too. The use of a reflective mulch to cover the soil around the plants may be effective in repelling aphids and thus help to limit the mosaic virus.

Lastly, it always helps to plant the right variety.  The University of Hawai`i recommends for bell peppers the following varieties: keystone resistant giant, summer sweet 760, grande rio, tambell ll, yolo wonder, California wonder, emerald giant, titan, midway, bell boy hybrid and banana large yellow. The hot peppers recommended are Anaheim chili, Hawaiian chili, jalapeno, long red cayenne and Hungarian. Check with your local University Cooperative Extension office for varieties in your area.

Monday, April 15, 2013

Replanted Vegetables Continue To Die

Why do vegetables continue to die no matter how many times I replant? There are soil borne plant diseases that can survive in the garden, either on plant debris or in the ground itself. Once infected, the soil can remain so year after year. Some of these diseases have a wide host range, while others attack either one particular species only or may attack members within a particular plant family. Planting the same crop year after year in the same location will allow for the pathogen to build up to high levels. 

One of the best control measures for the soil borne diseases is crop rotation. This will allow time for the plant debris to decay and the associated pathogens to die out. The time required for this to happen varies. Some diseases survive up to 10 years or more, but most recommendations suggest periods of one to four years before returning to the original crop.

Keep in mind that a fungus that attacks, for example, the roots of lettuce will usually not attack beans. If tomatoes are being grown one year, do not come back and plant tomatoes again, or potatoes, peppers and eggplant for that matter – they are all in the same family.  This is a good practice even if no diseases are detected.

Another important step in disease prevention is to take advantage of any resistant varieties that may be available. For vegetables, check with seed catalogs to see if they have varieties that are resistant to a specific disease. The same is true with fruit trees since certain varieties are more resistant to diseases.   

Note: resistant (or tolerant) does not mean immune. A resistant plant will be less affected by the disease and show fewer symptoms. A plant that is immune will not be affected by the disease. Unfortunately, some resistant varieties may lack certain desirable characteristics in the plant such as flavor or high production. If you can find resistant varieties, the battle against disease is half over.

Ask the Garden Guy, Science Based Answers to Garden Questions, is an excellent resource book for gardeners. Some popular topics include Slugs and Snails, Organic Pesticides, Reasons, Why Vegetable Seeds Do Not Germinate, What’s So Hot about Manure? Mushrooms in the Lawn.  Purchase by clicking on the image of the book above. 

Monday, March 4, 2013

Seedless Watermelon

 How do plant breeders obtain seed for a seedless watermelon?

 This is accomplished by making several different types of crosses between watermelon plants. Without going into a long genetic lesson, it first begins by doubling the number of chromosomes  (threadlike bodies in cells that contain  genetic information) in a normal watermelon plant.  This is done by chemical treatment. This new plant is referred to as a tetraploid because it now contains four sets of chromosomes instead of the normal two.  When the tetraploid plant is bred back, or pollinated, by a diploid plant, the resulting seed produces a plant that is basically a "mule" of the plant kingdom – one that produces seedless watermelons. The flesh of this melon is usually firmer than seeded varieties, because the usual softening of the fruit around the seeds does not occur.