Organic Gardening Tips and Methods Container Gardening (Pot - TopicsExpress

Organic Gardening Tips and Methods Container Gardening (Pot Gardening) Part Six Section Four Composts For Containers Special Composts, As well as ericaceous composts, there are other specialized composts produced commercially to suit the requirements of particular groups of plants. • Orchid composts, are free-draining and often contain charcoal and fine bark for good aeration. • Cactus composts, are even more free-draining, containing a high proportion of grit, and are usually low in nutrients. • Aquatic composts, which are heavy for better anchorage, are particularly variable as the major constituent ~ soil ~ is not of a consistent standard. • Bulb fibre compost, is made from undecomposed sphagnum moss, which has an open structure and o is suitable for growing bulbs in containers that do not have drainage holes. Modifying Composts, Both commercially produced and home-made composts can be easily adapted for particular plants or groups of plants. Perlite and vermiculite are commonly put in home-made composts to improve drainage and aeration. The addition of various grades of grit and sharp sand make composts drain more freely. Grit for example, is often mixed in equal parts by volume to JI No.1 to make a free-draining compost for alpine plants. Leaf mould, which is an excellent peat substitute in home-made composts, can also be added to ready-made composts to produce a moisture-retentive growing mix suitable for woodland plants. Mulches, Mulches are materials used to cover soils or composts to slow down water loss, to even out soil temperature fluctuations, and to discourage the growth of weeds. The most useful and neatest mulch for most containerized plants is grit spread evenly over the compost to a depth of approximately 1cm (10mm ~ 1/2in). A mulch of limestone chippings is suitable for alpines that prefer alkaline soils, while granite chippings can be used for lime haters. Coarse gravel is used as a top-dressing for trees and shrubs and can also help to stabilize containers. Organic mulches generally include granulated bark and cocoa shell; some of these tend to be blown about unless they are damp. Composted pine needles can be used for acid loving or ericaceous plants. Mixing Composts, The principal difficulty for amateur gardeners preparing their own compost is sterilizing the loam. Special soil-sterilizing units used for large-scale heat treatment are expensive, but smaller scale units are available from specialist suppliers. To treat small quantities, put the soil through a 5mm (1/4in) sieve to remove stones and lumps. Then spread it 8cm (3in) deep on a baking tray and bake for 30 minutes (half an-hour) at 200 degrees Celsius (400 degrees F ) in a domestic oven. Alternatively put the soil in a roasting bag and heat in a microwave on full power for ten minutes. Assemble the ingredients on a clean flat surface (for exact quantities, see Loam-based Composts). Mix the sterilized loam and peat substitute or peat (well moistened if it is dry). Combine the ground limestone and John Innes Base with some sand to ensure even distribution and incorporate this thoroughly into the remaining sand, loam, and peat substitute or peat. Environmentally-Friendly Growing Media, For gardeners preferring to grow plants in containers according to organic principals, it is important to choose a compost suitable for the type of plant to be grown in the pot. Long-term container plants such as shrubs need a loam based nutrient-rich compost that is also water-retentive. Use a mix of 1 part loam, 1 part general leaf mould and 1 part garden compost or well rotted manure by volume, adding a further part of 2mm grit if the plants require sharp drainage. Comfrey leaf mould, which is nutrient-rich, may be substituted for general leaf mould, if available. Short-term, quick-growing container plants as well as hanging basket plants ~ usually annuals or perennials grown as annuals ~ are best grown in a loamless or soilless compost consisting of 3 parts peat substitute or well-rotted leaf mould to 1 part comfrey leaf mould by volume. To improve water retention, an organic moisture retainer based on coarse seaweed meal may be added to the compost. In both cases, worm compost may be used in place of comfrey leaf mould as it is both water retentive and nutrient rich, a bonus for many of the quick-growing plants used. Common Ingredients For Potting Composts, • Loam; Sterilized garden soil, with good nutrient supply, drainage, aeration, and moisture retention. • Grit; Various grades of grit are added to compost to improve drainage and aeration. • Peat; Well-aerated and water-retentive, but low in nutrients. Hard to re-wet when allowed to dry-out. • Vermiculite; Expanded, air-blown mica acts like perlite, but holds more water and less air. • Fine Bark; Used as a peat substitute, especially in composts formulated for acid-loving plants. • Perlite; Expanded, volcanic rock granules retain moisture but drain freely. Aids aeration. • Coir; This peat substitute dries less rapidly than peat but needs more frequent feeding. • Sand; Coarse and fine (silver) sands aid the creation of more open textured composts. • Leaf Mould; Used as a peat substitute and compost additive, especially for woodland plants. And In General...... Composts For Plant With Special Needs, Azaleas and other rhododendrons are intolerant of alkaline soils. In a container they are best grown in an ericaceous compost, which is loam-based but lime-free. Good Drainage, To ensure good drainage, place terracotta pot shards (old-broken pieces of pot).in the bottom of a container; large pebbles and chunks of polystyrene are also effective as drainage material. NOTE; All information given coincides and complies to the guidelines of The Royal Horticultural Society (RHS).......