The remaining minerals a plant needs are Sulphur plus a string of trace elements. These are Iron, Manganese, Copper, Zinc, Boron, Chlorine, Molybdenum and Nickel. Deficiency of any of these can lead to disease and a few trace elements are toxic if present in excess. Generally speaking these are not detectable by the kits available to amateur gardeners and in practice even commercial growers send samples away to be tested professionally.
Getting at the details of what Magnesium and Calcium actually do are quite tricky because most gardening books tell you what happens if they’re not there and leave it at that. So after a bit of sleuthing this is what we came up with. Calcium binds the cell wall together and Magnesium makes Chlorophyll work. Plus the come free with the deal when you lime with carbonate to fix the soil pH.
For those who like doing things for themselves, one way of feeding the plants is to make your own liquid fertiliser. You can do this quite simply by using deep rooted plants like comfrey and nettles. These not only are high in potassium and nitrogen but also concentrate trace minerals from the subsoil. It’s really quite easy. You can buy one or more of those 50/75 litre waterbutts they have in B&Q or Homebase plus a tap for them. Fill it up with freshly cut roughly chopped comfrey and nettles (we sometimes put thistles in ours too) and then fill it up with water. Leave for 3-6 weeks – then dilute and use
Video to demonstrate what you need to do to test your soil with a soil testing kit. Covers pH and Nitrogen, Potassium and Phosphate.
So if you don’t have enough potassium, the plant will be stunted, it won’t elongate properly and it will go yellow. The reason it doesn’t flower is because it’s sick and the plant hormones that actually induce flowering aren’t made or released properly.
Why plants need phosphate is something that’s answered really poorly in most gardening books. You usually find something lame about it being necessary to promote rooting and flowering – especially as the best that can be said about deficiency is that the plants grow slowly without it and that they may show purple colouration in older leaves in some species.
Here’s the Biochemistry.
Phosphate is what the cells use for money.
The Intelligent Garden is keen to help you understand a the basics of plant science so you can get the most out of growing your plants and designing your garden. One of the key things is to understand the basis of fertility. Plants need nutrients – the big 3 are Nitrogen, Phosphate and Potassium –… Read More »
In order to grow effectively plants need to be able to get adequate supplies of nutrients and water so that they can develop without a check. Let’s face it as gardeners or indeed as commercial growers, a lot of what we do is aimed at making this so. Adding nutrients to the soil (or hydroponic… Read More »