Sunday, May 10, 2020

Raised Bed Gardening - Pros and Cons

Many people are drawn to raised bed gardening for several reasons.  In addition to the fact some areas do not have sufficient soil, raised bed gardens generally look nice and appear easy to maintain. In many parts of the United States, reasons for building raised beds are to keep gophers out or to have warmer soils in the early spring after the winter thaw. For portions of the Hawaiian Islands, gardening in raised beds or containers is necessary because of a lack of soil on lava hardened  terrain.  

Other reasons for building raised beds are 
 (1.) the soil may be extremely alkaline (a high pH) or acidic (low pH), 
 (2.) the soil is too compacted,  
 (3.)  the gardener needs wheelchair access and
 (4.)  the gardener prefers less stooping.

On the other hand something to consider is the maintenance of raised beds. If the frame is made of wood, it will eventually rot. If metal is used, it may rust. Actual construction of the bed can be time consuming and costly. In addition to wood, rock and plastic can also be used.

Two questions often arise. First, how deep to make the beds?  The literature gives a range of 6” to 18”.  Crops like lettuce, onion and bok choy will do fine in a shallow bed. Yet deeper beds are needed for carrots, parsnips, corn and tomatoes.  

Secondly, where to get good soil? You can buy bagged potting mix at the garden store, which can be very expensive. Or you can buy a truck load of soil but be cautious. Soil may look good, but you can’t see N-P-K deficiencies or excesses, pathogenic fungi, bacteria, nematodes or pesticide residues including persistent herbicides. Bringing in soil can be risky.

Installing raised beds can be a satisfying project. But first, find out what your particular problem is and why you are considering a raised bed. Perhaps correcting the problem could be a better solution, possibly cheaper and less time consuming.

Photos from University of Missouri.

Monday, March 30, 2020

Why fruit trees don’t produce.

Since there are many factors involved in fruit production, there are also many reasons why fruit trees don’t produce.  Here are a few of the more common ones.
·        Rain- Too much rain during the bloom period can wash pollen away,  and a forceful rain along with wind can actually knock blossoms off.  Also, bees tend to fly less, or not at all, during heavy rains.
·        High heat and low humidity during bloom will hamper pollination.
·        Juvenility  - Sometimes it takes many years before a tree will produce fruit; mangosteen is a good example. However, new evidence indicates the size of the tree is more of a factor than age. In general, trees grown from seed take longer to produce fruit than those that are grafted, budded, or air layered. 
·        Pollinators – Some fruit trees require more than one tree or one variety in order to set more abundant fruit.  Examples are rambutan, macadamia, and avocados.
·        Some trees require insects to help in pollination, such as durian. 
·        Lychee and longan need a combination of low temperatures, 50 -59 degrees Fahrenheit, and a dry period (4-6 weeks) before bloom occurs.  Bloom for rambutan will be enhanced in response to drought.
·        The deciduous fruit trees, like peach, plum, nectarine, apple, etc., require cooler temperatures for good fruit production. This chilling requirement is the number of hours the tree needs to experience below 45 degrees F.  This requirement differs among species and varieties, ranging from a few hundred hours to over a thousand. 

Monday, February 3, 2020

Cilantro or Coriander?

Most chefs are familiar with the seasoning 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. The fresh leaves and the small dried fruit are the parts most traditionally used in cooking.

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. The leaves 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.

The Problem of Bolting

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. 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.  

On the Big Island of Hawaii, the Volcano and other similar 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.

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. 
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.