Importing Soil Into The Garden – What You Should Never Do
Jonathan Ya'akobi If you have to bring in new soil to your garden, make sure your supplier is well known and recommended, and holds a license permitting him/her to excavate soil from properly authorized locations. The worst possible thing you could do is import soil which has previously been put to agricultural use. It will no doubt be a lot cheaper, but you know the saying -- "cheap is dear." In this case cheap could be catastrophic. Why is this so? Because many pests and disease are soil borne. *Agricultural soil is liable to contain seeds or perennial organs (bulbs, rhizomes, tuberous roots, etc) from weed species that are the most pernicious and difficult to eradicate. Examples in warm Mediterranean climates include the sedge that wreaks such havoc in third-world agriculture, Cyperus rotundus, the parasite Cuscuta campestris, and the perennial grass Cynodon dactylon. *It could contain soil borne diseases such as the fungi Pythium and Rhizoctonia. The latter can be particularly damaging to lawns, and extremely difficult to control. *Root nematodes are another pathogen liable to be present in such soils. Nematodes are microscopic worms that feed off plant roots. Susceptible plants like The Weeping Willow tree for instance, often die as a result of nematode activity. *It could also be full of eggs of pathogenic insects, most notably belonging to the dung beetle, Phyllopertha. The caterpillars of the dung beetle, if found in large enough numbers, can virtually lift up a lawn, as they disconnect the grass from its roots. * Agricultural land may contain residues in high concentrations, of pre-emergent herbicides that can seriously retard the growth of new garden plants and can even damage existing ones. Soil Tests Clearly it is vitally important to conduct a soil test on newly imported soil. Soil testing kits may be adequate where soil has been brought in from a reliable source, if however you are unsure where the soil has come from, it would be advisable to hire a professional company that will conduct a laboratory, soil analysis. In addition to discovering the hazards previously mentioned, a soil test should provide data on matters like nutrient levels, percentages of organic matter, soil salinity, and the soil's pH. A really professional test, based on laboratory data, is best for deciding what actions to take. Remedies *Some problems can be solved by a professional gardener, prior to planting the garden. Perennial weeds for example, can be eliminated following a laborious process taking some 12 weeks. The ground is watered profusely in order to encourage the weeds to grow, when they are subsequently sprayed with a systemic herbicide. *Dung beetles can be sprayed with an appropriate pesticide, or preferably by collecting them as they rise to the surface for air, following a deep watering. *Fungi and some weeds can be destroyed by solar sterilization, where a transparent plastic sheet is laid on the ground for some two months. The work, to be effective, has to be carried out in a season when the sun is at its zenith. It is best here, to consult with the soil expert. *Herbicide residues can be broken up by the incorporation of large quantities of compost, because the increased populations of micro-organisms, can include species that break down the chemicals. *The treatment of root nematodes on the other hand, is not within the competence of a gardener (including myself) and has to be conducted by a specialist in plant pathology. Once, chemical treatments were most common. Today though, biological control is increasing in use. Beneficial nematodes are added to the soil, as these by virtue of their parasitic properties, regulate the populations of the pest species. The best way of course of dealing with soil related problems is to try and avoid them in the first place. Prevention, as they say, is always better than cure, and one of the best methods of prevention is to refrain from importing cheap, agricultural soil into your garden. About the Author
I've been gardening in a professional capacity since 1984. I am the former head gardener of the Jerusalem Botanical Garden, but now concentrate on building gardens for private home owners. I also teach horticulture to students on training courses. I'd love to share my knowledge and experience with you. So you're welcome to visit me on www.dryclimategardening.com Jonathan Ya'akobi may be contacted at http://www.dryclimategardening.com/. Click here to view more articles by Jonathan Ya'akobi. Reprinted with Permission from IdeaMarketers.com
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