THE COMPOSTING RAISED BEDS

The technique of composting raised beds also known as the ‘mound culture.’ is the use of rotted wood and other organic materials to create low-input raised beds that are highly water retentive and self-feeding. It is a method that is based on the simple principles of decomposition that, when done properly, provides nutrients to the plants without the need to add externally acquired fertilizers for years while at the same time holding what water they receive for extended periods. They are therefore well suited to dry climates and production in areas where fertilizers are not desired, aren’t accessible or are prohibitively expensive. This method can be used in virtually any area to create permaculture beds that are essentially self sustaining indefinitely with the proper care and cultivation.
Mound culture beds are similar to other raised beds in composition apart from one key difference: the beds are built on top of a stockpile of rotted wood and other composting biomass, be it duff, leaves, wood chips or whatever else may be on hand. Because of the large mass of all this, the beds will necessarily be built high and so are most often the site for the bed is dug out a few feet. The depth to which the troughs are dug is determined by preference, the amount of time and effort one is willing to spend in building the bed (though this part is obviously greatly facilitated by the aid of heavy digging equipment), how hard the soil is and so on. For example, were you to want to make a mound bed in a neighborhood where there are restrictions regarding the appearance of a yard, it is possible to make the bed rise only a foot off the ground when in reality it may reach as far down as six feet. Most sources recommend a total height of at least four feet and ideally around six feet when the beds are completed, especially since much of this height will be lost in the first couple of years as the organic materials break down and thus compact slightly. If appearance is not an issue or there is only a limited amount of wood and organic materials available, it is perfectly suitable to simply build your beds on top of the existing ground level although you will then have to import soil from elsewhere. Typically the troughs are dug to a depth of about two to three feet with the soil and sod set aside separately, filled in with the rotted wood and other biomass, covered with the turf inverted so the soil side is up and then covered again with the remaining soil. After this, the beds are ready to be planted; indeed, as we will see later, there is good cause to plant the beds immediately.
It is possible to use a huge variety of materials, locations, soil types and so on when making a mound bed. There are, however, a few considerations that should always be made before building one. Location is the first and foremost of these. One should take several factors into account when choosing a site for the bed. Sunlight, as always, is the foremost of these, and as such the beds should be oriented to maximize sunlight throughout the day (South-North Orientation). If you wished to grow plants that needed indirect light, an east-west orientation would give you one side that received less light through the course of the day. Slope is another important consideration, and if the beds are to be built on a sloping surface it is perhaps the most crucial. This is because the beds are so absorptive that if they are not oriented properly with the flow of water, they will become over saturated. Were your beds to run perpendicular to the slope then those at the top would catch all the water, leaving those at the bottom deprived and dry. If the opposite orientation is employed, the water would simply sheet down the hill which could lead to massive soil sloughing and even landslides. Therefore, what Holzer is suggesting is that you take note of which way the water flows and then position the beds on a slight bias to the slope with offset breaks between them. This way the water will flow down along the sides of the bed allowing them to absorb some but all until it reaches the end of the bed and then passes through the break, down to the next row of beds, thus evenly distributing the water between all beds while slowing its roll down the hill. Accessibility is another factor worth going into. The placement of your beds should be in an area that is easily reached and that can accommodate the desired length and height of your beds with plenty of room between them and on the ends to facilitate plantings and harvests.

Though the choice in plants ultimately comes down to what you wish to grow, as with any permaculture scenario it is always to have a well thought out and diverse array of species that will complement one another in their growth. It is also important to think about planting deep rooted perennials for two reasons: one because they will add to the overall structural soundness of the bed but also because their long roots will draw moisture up to the benefit of other, shallower rooted plants. Another important factor to bear in mind is decomposition level of the organic material used in the bed previous to building. If your materials are small and only slightly composted, then you can expect high levels of nutrient release in the first few seasons and so you should plant accordingly with high demand plants such as cucurbits, night shades, and apiaceae (Holzer, 2011). You can then move on to less demanding plants like legumes (even better as they will fix nitrogen and add to the fertility of the bed) in later years. Mulch crops are also recommendable, and these again will be determined by all of the factors stated above. Strawberries are a good example, as they spread easily, are good for shading out the ground beneath, are hardy enough to be cut back to make room for planting and have the added value of producing an edible fruit. It will also be to your advantage to plant a resilient cover in the aisles between your beds; something that can withstand foot traffic but at the same time keep the soil in place.
Again, the best part of hugelkultur is how open-ended it is at every turn. As long as the basic principles are in place, then chances are your beds will flourish. Hugelkultur may afford those who have little water a viable option for growing much more than they could without the massive water storage capacity of the wood. It also creates an excellent use for wood and other biomass that might simply go to waste otherwise. If nothing else, it provides an interesting experiment that is a great alternative to normal raised bed gardening. This article really only scratches the surface of possibilities regarding hugelkultur. Its applications and variations are seemingly endless, they need only be implemented and, of course, shared with the world.
 For more reading visit: http://www.agrowingculture.org/2013/04/hugelkultur-the-composting-raised-beds/

GREENHOUSE NEMATODE MANAGEMENT

Nematode problem is common in greenhouse production. Many farmers still are not able to identify nematode problems in their crops with certainty. The most common species of nematodes identified in greenhouse production are root knot (Meloidogyne), lesion (Pratylenchus), Burrowing (Radapholus), and leaf stem, or foliar nematodes (Aphelenchoides or Ditylenchus).Nematode problems affecting greenhouse crops and commodities can be avoided if appropriate pest management practices are considered.  

Nematodes, a group of specialized worms, live almost everywhere. Some are PLANT PARASITES. Most greenhouse farmers do not know about plant-parasitic nematodes as they are very small (less than 1 mm long) and can be seen only through a microscope. Nematodes infest roots, rhizomes, bulbs, stems and also live in soil. Unlike other pathogenic organisms, it is very difficult to identify plants affected by nematodes. These plants generally look sick and symptoms may be confused with other root diseases (e.g. yellowing caused by Fusarium wilt) or nutrient problems.

Occasionally infested plants are stunted with burning/drying of tip leaves. Planting pieces infested with nematode looks shriveled, with sunken or swollen patches on the skin surface. Infested plants have swollen, distorted roots. Infested rhizomes have warts on the surface. Heavy nematode infection can greatly reduce yields. Select planting material as free from nematodes as possible.  

Causes of nematodes build-up in soils 

In most cases, problems with these nematodes arise from planting of infected seed or planting-stocks, in systems utilizing bare ground or raised ground beds.

Secondly, contaminated soil is used as a component of the growing medium. Subsequent spread of nematodes within the greenhouse usually occurs via movement of infested soil or plant material by workers, water, or greenhouse equipment. In some greenhouse systems, nematodes can be introduced into and circulated through the drainage system and irrigation water to other healthy plants within the greenhouse. This explains how once introduced, nematodes can quickly spread and become headache in greenhouse production. 

Nematode Management Practices and Considerations 

For greenhouse production, nematodes must be managed through exclusion and avoidance (prophylactic strategy). Once nematodes are introduced and damage becomes visible, it is currently not possible to chemically or non-chemically resolve the problem to avoid potentially significant yields losses thereafter. Some of the most important sources of contamination and hence major factors to consider include: 1) seed and planting stocks, 2) irrigation water, 3) soil and potting media, and 4) general cleanliness.  

Site Selection

Among the common considerations for greenhouse location like: proximity to water source, security from thieves and destruction, windbreaks etc, there are also important pest management considerations. 

Greenhouses location should be shielded from pest migration paths especially from neighbouring farms. This will be achieved by guarding the greenhouse with nets and avoiding very open fields.

Ensure the soils to be used are free from nematodes of economic importance because nematodes are very hard to eradicate once introduced ion the greenhouse. In addition, greenhouse structures should be stored such that they will not be exposed to running water downstream that might be transporting nematodes or other soil borne diseases with them.

Irrigation 

Water from shallow wells (hand-dug water holes) has been noted to bear high quantities of nematodes. Similarly, water from ponds and other stagnant sources that rely on surface runoff have known to harbor nematodes. In the event that these waters are used, there should be proper treatment prior to use for greenhouse irrigation and/or for preparation of spray mixtures. This treatment should be extended to recycled water from the greenhouse. The simplest method of water treatment for use in the greenhouse is heating to temperatures beyond 90°C.

Nematode-Free Planting Materials  

In most cases, greenhouse problems with both soil borne and foliar nematodes arise from planting of infected seed or planting stocks. As a result, nematode-free transplants or plug plants that rely upon soilless substrates from production are increasingly used to exclude foliar and soil borne species of nematodes, but also to expedite plant establishment and crop production.

 In addition, hot water dips have been developed as a control strategy to eliminate plant-parasitic nematodes form both roots and foliar tissues of infested plant materials to be used as transplants (e.g., strawberry, ginger etc).

To destroy nematodes in plant material, dip seed pieces in hot water (50°C) for 10 minutes, then remove, and cool. Fungicide dip treatments can be done following the hot water treatment. Plant the treated seeds within 2-3 weeks of treatment.

Sanitation 

Other cultural measures that reduce nematode problems in the greenhouses include rapid destruction of infested crop root systems following harvest. Discarding infected potted plants will help prevent spread of nematode. Entry points for greenhouse structures should also contain sanitizing stations for hands, shoes, boots, tools, and other equipment.

Soil pasteurization (Soil heating) 

On a relative temperature scale, nematodes and water molds would be considered relatively intolerant of high temperature, being effectively killed by 30-minute exposure at temperatures as low as 50°C. Within the range of 50-60°C, most plant pathogenic fungi, and bacteria are killed. Certain weeds and viral pathogens compose the most tolerant group, requiring 30-minute exposures at temperatures of 60°C or greater for pest elimination. A 30-minute exposure of 90°C or greater is generally recognized as the recommended soil pasteurization temperature and the period of exposure to provide a broad spectrum measure of soil borne pest and disease control. The following section defines specific pest control systems that rely on heat to control nematodes in greenhouse production.

Soil Solarization (Heating with the Sun) 

Soil solarization involves application of a transparent polyethylene plastic mulch over moist soil for a 6 to 12 week period to heat bare (but ploughed), greenhouse soils to temperatures lethal to nematodes and other soil borne pathogens prior to planting. Soil temperature rises because of the trapping of Sun’s radiation under the clear polyethylene plastic. To be effective, soils must be made thoroughly wet to increase susceptibility of soil borne pests and heat reception and retention of soil.

Use of Resistant Host Plant

Most  crops have resistant varieties to nematodes. Use of nematode-resistant crop varieties is often viewed as the foundation of a successful integrated nematode management program.

The surest way of managing nematodes is through prevention of entry into your greenhouse soils.

SOIL SALT ACCUMULATION IN THE GREENHOUSE. WHAT TO BE DONE.

Soil salt accumulation, airborne diseases and greenhouse pest are the common problems faced by greenhouse farmers. Today, I want us to look at soil salt accumulation.

Greenhouse soils are held in continuous production for a long time under conditions of heavy leaching. As a result, micro nutrient deficiencies are a common problem and most farmers mistake them for pest effects or diseases on crops. Under these conditions plants will exhibit nutrient deficiency and toxicity symptoms. Accumulated salt levels will hinder absorption of micro nutrients by plants. 

Salt accumulation in soil is occurs when there is accumulate fertilizer and fertilizer residues, stagnant water in the soil in the absence of leaching, precipitation or plant uptake, cropping system (no rotation plan), irrigating with water with modest amount of salt and application of sprinkler and /or flood irrigation in hot arid climate.

Soil testing, which involves PH and soluble salt level analysis, is the sure way of ascertaining the levels of micro nutrient deficiency and toxicity levels in soil to warrant appropriate action. it is essential that every greenhouse farmer has a PH meter to analyze soil PH regularly and an EC meter to test the soluble salt levels. More accurate and elaborate analysis can be done in commercial institution laboratory available in the country. However, the most simple and quick way to evaluate soil nutritional status is by visual diagnosis. When observing a disorder, the plant parts affected must be noted as well as their respective ages. are the symptoms on the stem, fruit, flower or growing points of the plant? What is the nature of the ailment? Is the tissue chlorotic (yellow), necrotic (brown) or deformed? With the right description of the color pattern and location of the disorder (necrosis, chlorosis or deformation), You can find assistance from a qualified crop specialist.

Foliar(leaf) analysis is another very effective method of assessing the nutrient status of plants. Leaves are sampled and collected at a particular stage of crop development. Because nutrient content on a plant varies with leaf position, collect similar plant parts from sampled plants in you crop field/greenhouse for comparison against a standard.Routinely, samples need to be taken every four to six weeks otherwise immediately in case of suspected growth problem. Samples taken should have been grow under similar conditions ie root media, fertigation and husbandry.Some plants are very sensitive on slight fluctuation in soil nutrition. You need to grow such crops amongst the other high value crops. some of the best indicator crops are; lettuce, cucumber and tomato.

Fertilizer application and soil PH regulation are the treatment to these plant disorders.

To manage salt accumulation in the soil, encourage leaching of excess salts and remaining with only the required amounts in soil, drain excess salts, improve on fertilizer management, do soil amendment (correction) and water treatment.

Facts about Greenhouse Technology

Recently, Greenhouse technology has become popular among many farmers, both novices and pros. While many have seen zeros in their bank accounts increase as a result, many have recorded huge loses after massive crop failure in this plastic houses.
Greenhouse technology has numerous advantages to farmers particularly in the wake of increased land fragmentation, environmental pollution, vagaries of climate change and increased pests and disease resistance to agrochemicals among other reasons. However, in the quest of attaining the many gains, as will be listed below, many farmers overlook the main determinants for employing this technology in an individual's farm.
Firstly, greenhouse technology began in the temperate regions where environmental conditions during winter could not support outdoor crop production. In producing high value off season crops, farmers used controlled-environment agriculture. Greenhouses will only be profitable when doing high value crops that will not survive outdoor production. This explains why tomato remain the most common crops grown in many greenhouses I have visited in the country.
Secondly, Greenhouses are known not to perform very well in areas with continuous high temperatures. Crop production under temperature regimes beyond optimum is adversely affected and flowering interfered with. Farmers should seek professional advise in determining suitability of greenhouse farming in their geographical locations.
Thirdly, greenhouse technology calls for intensive management compared with outdoor production. it is for this reason that modern greenhouse are fitted with automatic control systems for greenhouse environment. Until farmers realize this fact, greenhouse may not be the ultimate solution to crop challenges.
Lastly,  Greenhouse technology is a high investment venture right from construction to management. This explains why it is exclusive for high value crops during off season production only. So if planning to venture into protected cropping, consider the points listed above and you will be a sure winner greenhouse in crop production.