Now that the temperatures are slowly edging up and some light rain has finally appeared, have you noticed how crazy the gardens are going? It may still look like winter out there, but there's a feeling that with the slightest encouragement, buds will be bursting out all over the place.

 

Interest in organic gardening too has been growing in recent years, and there are many people who would either like to exchange experiences and or would like to learn more about it. If you are curious about practical organic gardening, West London Organic and Wildlife Gardeners Association   have been holding short Grow Organic courses on allotments in Ealing and Acton for the last two years. The courses were lively, with everyone contributing from their own experiences, and for only around £12- £15, excellent value. If there is enough demand, they plan to run them again this year, so email cyberose@waitrose.com to let them know if you would be interested.

 

Francis House, gardener and organic allotment holder, explains some of the background to organic gardening and the reasons why gardeners have become interested in it.

 

�Since the advent of farming, farmers have used what we now refer to as �organic' methods. Then came the Second World War and Great Britain was blockaded. Those times, when we needed to supply our population with food, called for desperate measures. The scientists knew that plants needed three major nutrients in varying proportions; Nitrogen for leaf growth, potassium for flower and fruit and water uptake and phosphorus for the synthesis of carbohydrates. They discovered that plants could use these chemicals in an almost raw form and so was born �National Growmore'. Inspired by their success, they continued to produce synthetic chemicals for a variety of horticultural uses. Two things they had failed to take into account: that nature is a complicated system of interconnected relationships, and that many of the synthetics they were using were far more potent than they had realised.

 

One of the first problems to appear with synthetic pesticides was with DDT, an insecticide. Although it isn't highly toxic, it accumulates in the body of humans and animals because it degrades extremely slowly in the environment and is removed very slowly from animal tissue. Since then we have realised that relatively harmless pesticides can have long terms effects, and we should minimise our contact with them.

 

Synthetic fertilizers are soluble salts of phosphoric acid, ammonia and potash. They can damage the root hairs on a plant that the plant needs to take up water and nutrients. This can kill the plant if used in excess. They provide an immediately available source of phosphor, nitrogen and potassium. However they quickly leach out of the soil and often end up in waterways and your drinking water. This causes problems with algal growth which clog up waterways and your pond. To see this in action take a clear plastic bottle and fill it with tap water. Do up the cap and leave it on your windowsill for a week or two. Take a bottle of mineral or spring water and leave it next to it for the same time. The leaching process also means that the level of nutrients available to plants varies widely. The manufacturers' answer to this is slow release formulations such as �Osmocote'. The problem with this is that these chemicals are highly reactive and will react with one another creating stable insoluble salts which are therefore unavailable to the plants.

 

The traditional means of supplying nutrients was through animal manures and derivatives, composts and leaf mould, wood ash, seaweed products and mineral deposits. Animal manures provide the most immediately available source of all the major nutrients plus some minor nutrients, but they need to be properly composted or they suffer from the same drawbacks as the synthetic fertilizers.

 

Manure, compost, leaf mould, seaweed and similar organic materials provide humic acid, which reacts with clay to form humus, which holds nutrients in the soil. Wood ash provides potash and reduces acidity, and the mineral deposits provide potassium and phosphor. All these need to be broken down to be available to plants, and the conditions they need to be broken down are the same as plants need for growth. Therefore they provide nutrients when plants need them, and don't then get washed out of the soil. By adding these natural materials to the soil you make the soil fertile on a long term basis, only needing the occasional top up. While it is more expensive in the short term, in the long term it pays back.

 

Although some synthetic fertilizers you can get will include some of the micro-nutrients plants need, none of them provide all. These micro-nutrients are what plants need to be healthy and most importantly disease resistant. They are also what give fruit and vegetables their flavour. Being soluble they are at high levels when first applied then become quickly depleted. This causes the plant to alternate between rapid growth and slow growth. In the rapid growth phase fruit and vegetables take up a lot of water and make a lot of carbohydrate, which also contributes to lack of flavour. They will have lower levels of many nutrients that humans need. People will therefore have to eat more carbohydrates to get sufficient of the other nutrients.�

 

So don't forget, if you would like to learn more about practical organic gardening, email cyberose@waitrose.com to register an interest in the West London Organic and Wildlife Gardeners Association short course.

March 27, 2006