Understanding Fertilizer
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Wet weather can leave our crops and plants on the hungry side as nutrients are leached away, especially if you garden on light and free draining soil. Therefore it is important to understand how fertilisers can help to improve your crops and plants. All fertilisers contain at least one of the major plant foods-that is: Nitrogen (N) for stem and leaf growth Phosphate (P) for root growth Potash (K) for flower and fruit production
Plants also need trace elements such as iron, magnesium, boron and manganese. Some fertilisers contain these as well.
All proprietary brands of fertilisers, whether in bags or bottles, should display the analysis or the N:P:K ratio. For example, if the N:P:K ratio is 7:7:7, as in Growmore, you know that it contains equal parts of the three major plant foods and therefore suitable for general use with all plants. Every plant requires all three elements, but at different stages of growth and they are needed in different proportions. For example, a flowering or fruiting plant, and many vegetable crops, requires some phosphate in the early stages, to promote root growth, followed by a fertiliser high in nitrogen for the growth stage and then one which is higher in potash to ripen the plant and assist in flowering and fruiting.
Blood, fish and bone is a chemical-free version of Growmore, with a similar amount of the three major plant nutrients making it suitable for any edible crop, but keep it away from those you eat raw, such as raspberries and strawberries.. Perfect for long term crops, such as parsnips and fruit trees.
Bonemeal a slow release organic source of phosphate to promote strong plant growth. Incorporate a little into the planting hole for new plants and sprinkle around the base of existing trees and shrubs.
Sulphate of Ammonia is strong stuff! It’s what’s known as a straight, which means it just contains one nutrient in a high dose! High in nitrogen, sulphate of ammonia will boost peas and beans that are yellowing, especially when plants are young. It is also good for brassicas and leafy crops such as cut-and-come-again lettuce. Also good for activating the decomposition process of your compost.
Sulphate of Potash is a fast acting source of potassium for developing healthy fruit and flowers.
Iron Sulphate for acid loving plants and can be used to feed ericaceous plants such as azaleas, heathers and camellias.
Chicken manure pellets are a great general fertiliser because they are natural, easy to handle and spread and high in nitrogen (N). Also contains levels of (P) and (K). Use it on crops you grow in rows such as runner beans. Just scatter it at the base of the plant and “job done”.
General granular feeds such as Growmore are similar to blood, fish and bone, but not suitable for organic gardens. Normally contain equal parts (N):(P):(K). Growmore was first formulated as part of the “Dig for Victory” campaign in the second world war—hence its full name “National Growmore"
Tomato Feeds can be used on any crops to help promote flowers and fruits. Normally sold in liquid form and applied weekly after the first fruit has formed.
Magnesium Sulphate (Epsom Salts) is a quick-fix foliar feed applied straight to crops where the leaves are suffering from a nutrient deficiency. They work best on soft young leaves. Raspberries are prone to this deficiency. Should be applied on a dull day to avoid scorching.
Superphosphate for root crops. Apply in the winter for best results.