Phosphorous and clay soil aggie horticulture
September 3, 2015
Acid Phosphate Fertiliser
Dating back hundreds of years ago, almost every acre of farmland has had someone put some kind of fertilizer on it. If you are thinking about starting a garden, the sooner you get started the better. But, how do you go about fertilising? And why?
At the top of the list of fertilisers are “acid” or acidifying fertilisers. A lot of gardeners choose to use acid (calcium) phosphate fertilisers because they are quite readily available, and are often low in price. They are the most commonly applied “hot” fertiliser in the UK, yet are notoriously difficult to use in achieving the desired results. An application of a typical 21g / 1L size can only use-up just over half a ton of these fertiliser types, therefore, if you do not get the results you want, there is not much you can do about it!
Most other gardeners opt for “base” fertilisers. The reason for this is because they are cheaper, can be bought at higher concentrations, and are therefore “applied more easily”. There are three main types of base fertiliser, and a combination of these can be used to great effect in achieving your gardening ambitions.
Inorganic (as opposed to organic) fertilisers do have certain benefits though. For example, if you are looking to cultivate plants such as fruit trees, they contain higher nitrogen and phosphate levels than organic sources, and therefore they offer more to the plant. Inorganic fertilisers will also provide a rich source of potassium to your soil. As well as this, they do not require watering, and in fact, many have a negative effect on soil microbes because they can cause more organic matter to leach into your water table than can be retrieved.
A combination of base and acid can offer great benefits to your plants – in other words, you can use different varieties of these fertilisers for different seasons, or over the course of a growing season. However, both base and acid fertilisers have some disadvantages as well. While a lot of gardeners seem to believe that a mixture of these two types of fertiliser is the “holy grail” of gardening, what is often forgotten is that acid and base fertilisers require very different amounts, and usually applied very differently. If you combine the two, you may find that you are diluting your effect, and a far worse “system” than if you used a well considered single source of nitrogen.
As an example, if you plant tomatoes from seed indoors, and provide a very high level of fertiliser at this stage, a mixture of organic nitrogen with a variety of different types of fertiliser can be very beneficial. If you provide a consistent supply of an organic nitrogen source such as blood and bone, and make sure your plants get adequate access to water, they will grow to be a lot larger, and more robust than those plants that are neglected. But if you have to make a decision as to which inorganic fertiliser to apply, you should probably go for the type that is nitrogen rich. Acid fertiliser on the other hand should be used as soon as you have germinated the seed, and well before the seedlings have formed their first leaves. Phosphate fertilisers are good for your houseplants, but are too expensive to apply to your food.
There is no magic fertiliser. There are, however, many guidelines and theories which can be used to put the right type of fertiliser in the right place.
The Bigger Picture
After your soil has been tested for, and any amendments (additions) to your soil have been applied, there is still one more crucial factor that needs to be considered, and that is the amount of water your soil has available to work with. In this regard, soil is your “backbone”. Without it, you have nothing. If you try and work “with” your soil, rather than “on” your soil, you may have problems. Most people, especially those who garden at a commercial level, know that the first plant is often the one that takes the most work. That is because the first seedling, or sapling, can be large, and therefore quite difficult to support.
For this reason, more often than not, the first plant you take out is likely to be the fruit tree you have chosen to be your first one. In reality though, many a gardener will have plants growing in pots that are providing nothing to the soil. If you are choosing to buy fruit trees, you need to choose a healthy young tree that will make the best contribution to your soil. This usually means buying or growing from the good seed. But, you may even end up buying “older” trees because the fruits can be bigger. And if you have a big garden, you may be choosing a plant that will be taller. In this case, you will also be choosing a plant that has had less opportunity to develop a thick and strong root system to help it to grow more quickly.
Unless your garden is situated on a raised bed, or you are using a veranda box or other structural device, you will need to worry about providing for the drainage of any extra water that falls on your plants. This may mean digging a “garden pit” beneath your plants to ensure the extra water does not create unsightly puddles on your lawn or drive. In this case, a mixture of sand and pebbles will do a good job of draining water from the soil and also retain the nutrients that are in the water, helping the plants to thrive.
If you are choosing to buy a compost-based potting soil, you can find plenty of advice on the internet as to how to build this type of soil up. If you are trying to grow your plants outside, in the open, and in containers such as a wheelbarrow, a drip irrigation system is best. This system will allow you to water only those plants that you have chosen, and apply fertiliser