If anaerobic conditions develop this will lead to putrefaction and the production of various nasty and smelly compounds, including volatile fatty acids such as acetic acid, propanoic acid and butyric acid; sulphides such as hydrogen sulphide and mercaptans; and amines such as ptomaines derived from partly degraded proteins. Because most microbes work best at temperatures of around 40?
Any smaller and the resulting surface to volume ratio will be too great and the heap will lose heat more quickly than it can hold on to it.
If your heap does warm up, you can congratulate yourself on your technique, because it indicates high levels of aerobic decomposition. But remember also that too much heat can kill the microbes - most species cannot survive at temperatures above ?
The actual decomposition process takes place in a number of stages. Early on, the more readily putrescible materials - such as vegetable and fruit scraps - and the simple carbohydrates starches and sugars and proteins they contain, are converted by microbes into compounds like fatty and amino acids.
These, in turn, are consumed by other microorganisms. As composting proceeds the microbes oxidise carbon to get energy and the C:N ratio gradually declines as carbon is lost as CO 2.
Around two-thirds of the carbon that the microbes consume is given off as CO 2. The remaining third is incorporated along with nitrogen into their cells and released later when they die.
In finished compost, the C:N ratio will be about Aside from CO 2 , other byproducts produced by the microbes include water and ammonium. Towards the end of the composting process, nitrifying bacteria convert some of the ammonium into nitrates NO 3 - that plants can use.
Compost microorganisms operate best at pHs between 5. As the microorganisms digest organic matter they release organic acids. This can result in an initial lowering of the pH. But provided enough oxygen is present, these acids are neutralised as composting proceeds, and the finished material generally has a pH in the range of 7 to 8. If anaerobic conditions develop, the acids may accumulate. If this happens, mixing the heap to add oxygen is an effective way to reduce the acidity.
Earth to earth Although the amounts of nutrients that compost contains are often over-estimated, garden compost is a valuable source of humus. Even when only partly decomposed, it still works as an excellent soil conditioner that can help to improve soil structure, support soil life and recycle nutrients.
Composting is also being increasingly studied as a useful means to dispose of organic waste that might otherwise go into landfill.
Of the over m t of waste produced by commerce, industry and households in the UK every year, an estimated third of the household waste could potentially be composted. Statutory UK government targets call for local authorities to recycle or compost at least 25 per cent of household waste by This adds up to 8m t and provides a strong incentive to investigate ways of composting on a larger scale.
Now that should really make your garden grow. Clay minerals consist of a series of plate-like layers comprising sheets of silicon, aluminium, magnesium and other cations surrounded and held together by hydroxyl groups. Impurities are often found in the layers of clay minerals, resulting in a permanent negative charge. In contrast, the charge in the aluminosilicate materials - which develops in association with hydroxyl groups that can form at the broken edge of crystals - varies depending on the soil pH.
In alkaline soils the charge is negative, but in acid soils the charge is positive and the soil has an anion exchange capacity that can be satisfied by taking up negatively charged ions such as chloride, sulphate and nitrate.
Humus is a mixture of non-crystalline colloids synthesised by microorganisms in the soil from the breakdown of products or alteration of plant and animal materials.
Humus colloids consist largely of carbon, hydrogen and oxygen. They have a pH-dependent negative charge. As a result, humus, like clay minerals, adsorbs cations. In contrast, the availability of nitrogen is controlled more by the action of soil microbes than chemistry. In some plants, notably legumes like peas, symbiotic nitrogen-fixing bacteria allow them to take advantage of atmospheric nitrogen gas. In most areas of the UK, pink is the common colour for hydrangea flowers, but with a bit of clever chemistry, hydrangeas can be induced to produce blue flowers.
Although Victorian gardeners often sang the praises of blue hydrangeas, they found that producing them was a bit of an uncertain operation. The Victorian recipes involved watering hydrangeas with water impregnated with substances such as alum Al 2 SO 4 3. But the results were, Mrs Loudon admitted, a bit hit and miss. Hydrangea fanciers now recognise that the colour change in hydrangea flowers occurs when the plants take up aluminium from the soil - and this is largely controlled by the soil pH.
To produce blue blooms in soils where aluminium is present, the soil pH needs to be lowered to 5. Adding organic matter is one way to achieve this, but adding aluminium sulphate is sometimes favoured because, as well as reducing the pH, it also ensures that aluminium is present. If the plants are in the ground, the recommended dose is roughly 3g aluminium sulphate per litre of water. In pots the concentration should be reduced to 1. Nightsoil - human faeces and urine - was once highly prized as a high quality fertiliser.
In Victorian Britain popular garden reference books were singing its praises. These days the use of human manure, whether composted or not, is not officially recommended.
In the not-so-distant past urine was also prized as a foliar fertiliser. The fertilising properties of human urine are also the subject of modern scientific studies.
For example, a recent project carried out by the Danish Environmental Protection Agency, part of the Danish Ministry of the Environment, examined the potential for using human urine as a fertiliser on organic farms. The study involved collecting urine from the residents of the Svanholm Gods organic farming collective - the largest producers of organic vegetables in Denmark.
In addition, researchers also measured the levels of pharmaceutical residues, and artificial and natural hormones and heavy metals - all of which might constitute environmental hazards. Younger children love making mud pies Grow interesting plants such as sunflowers, corn, pumpkins, tomatoes and strawberries.
Use a trellis or teepee to grow beans or sweet peas. Plant flowers that attract butterflies, ladybirds and other interesting insects or birds. Make a scarecrow. Install a water feature, a birdbath or a sundial. Set up a worm farm. Child safety in the garden To make the garden safe for children: Select the correct-sized tool.
Keep sprays and fertilisers out of reach. Do not use chemicals. Garden organically whenever possible. Provide safe storage for equipment and tools. Secure fences and gates. Provide shade in summer with umbrellas or shade cloth. Do not leave buckets of water unattended around very young children and toddlers. Plant selection for children Children like large, brightly coloured flowers and vegetables that grow quickly.
Plants such as sunflowers, corn and pumpkins are good examples. You should also consider using varieties of plants that have sensory and textural qualities as well.
Different-aged children in the garden Toddlers, preschoolers, primary-school-aged and older children will all have different expectations and will learn different things in the garden. Younger children will require careful supervision during activities. Suitable tasks for younger children include watering plants, harvesting produce and planting seeds. Older children are physically capable of handling a greater variety of activities, like digging, carrying, planting, mulching and pruning.
Where to get help Community or local garden groups Cultivating Community Tel. Learn more about the different types of homeowners insurance. Benefits of Growing Your Own Food. Tips to Help Improve Soil Fertility. How to Grow Vegetables at Home. Backyard Pool Landscaping Ideas. Choose the right location Choose a location for the garden that has plenty of sun, ample space and close proximity to your hose or water source. Select your veggies Decide what produce to include based on your climate, space, tastes and level of expertise.
Prepare the soil Mix compost and natural fertilizers into your garden to condition the soil for your plants.
Check planting dates Growing conditions and ripening cycles are different depending on the plant and the season, so you should not sow all the seeds at the same time. Plant the seeds Place your seeds or plants into the soil, following the depth and spacing directions carefully. Add water Gently spray the garden with water to keep the soil evenly moist throughout the growing season.
Keep the weeds out Mulching is the most effective way to prevent weeds.
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