While doing some research on the internet about the N:P:K (Nitrogen: Phosphorus: Pottasium) values of fertilizers, I stumbled upon some interesting information about fertilizers that I would like to post here for sharing.
1) Different NPK Values
Do you know that different manure has different value of NPK percentage in it. This information was obtained from the Allotment Vegetable Growing website:
Chicken Manure (1.1: 0.8: 0.5)
Sheep Manure (0.7: 0.3: 0.9)
Rabbit Manure (2.4: 1.4: 0.6)
From the figures above, rabbit manure has a higher value of Nitrogen & Potassium nutrients. My friend, Elicia, whose children rear rabbit, uses the rabbit manure to fertilize her herbs patch. Now I can see why her herbs grow so well.
Note: Both cat and dog droppings can carry organisms harmful to human beings. Dog droppings can contain the eggs of the parasitic worm, toxocara, which can also infect humans. Cats can carry toxiplasma, another disease that can be passed on to humans. Accordingly, it is safer to dispose of these elsewhere rather than use them
More information on farmyard animal manures.
2) Facts about Nitrogen
Nitrogen has the shortest life in the soil as it is easily washed out by heavy rain. To increase Nitrogen content in your soil, try to plant legumes (such as peas, groundnuts) . My friend, Chooi, said her mom used to grow groundnuts among her vegetable. Legumes produce their own nitrogen due to a symbiotic relationship with bacteria that fix nitrogen from the air for the plant, which is why peas generally need no nitrogen supplement.
VERY HIGH Nitrogen requirement: cabbages, brussel sprouts, rubharbs
HIGH Nitrogen requirement: beetroots, celery, spinach leeks
MEDIUM Nitrogen requirement: brocolli, cauliflower, lettuce
LOW Nitrogen requirement: asparagus, parsnip, onion
VERY LOW Nitrogen requirement: carrot & radish
NO Nitrogen requirement: peas & broad beans
Apply More Fertiliser for Light Soils
Light and free-draining soils, usually sandy in composition, lose nutrients more quickly than other types, especially in rainy spells. Apply fertiliser more frequently on these soils, especially nitrogen fertilisers to maintain levels as Nitrogen is easily washed away.
Apply Less Fertiliser for Clay Soils
Heavy clay soils and soils containing a lot of organic matter require less frequent application. This is because both substances act as reservoirs holding the nutrients and releasing them slowly over time to the plants
Very Acid or Very Chalky Soils
Phosphates and potassium become more soluble in acidic soil, making them easier for rain to wash away. In chalky (alkaline) soils, phosphate becomes insoluble when mixed with the calcium present in chalky soils. In both cases, divide the application into two or three and apply over the growing season.
Lime and Fertiliser
Never apply or store fertiliser and lime together. There will be a chemical reaction between the lime and the nitrogen in the fertiliser, making neither effective. Especially when growing vegetables, check and adjust if necessary the pH (acidity) of the soil. Acidic soils may contain nutrients but they are less available to the plants.
Feed at the Right Time
Only add fertilisers to plants before and during the growing season. Applications made after the season will just be washed out of the soil and not do any good unless you use an over-winter green manure crop to hold them for the next season.
Boosting Failing Plants
If plants are showing signs of nutrient deficiency then you can give a boost using liquid fertilisers that are absorbed more quickly by the plant. Sometimes the problem isn't the amount of nutrient available but a lack of micro-nutrients preventing take-up by the plants. Try a spray of seaweed extract or a foliar feed with Epsom salts to release the nutrients. (see Additional Elements in Plant Nutrition)
Make Your Own Liquid Feeds
If you have comfrey (an important herb in organic gardening, having many fertilizer and purported medicinal uses) or nettles available you can make your own liquid fertiliser by adding the leaves into a barrel of water and allowing them to ferment for three of four weeks. This will make a fertiliser high in potash, great for tomatoes and hanging baskets. A high nitrogen liquid feed can be made by suspending a hessian sack of horse or sheep droppings into a barrel of water until the water turns the colour of tea.
Notes on Nettle: The growth of stinging nettle is an indicator that an area has high fertility (especially phosphorus) and has been disturbed. Nettles contain a lot of nitrogen and so are used as a compost activator or can be used to make a liquid fertiliser which although somewhat low in phosphate is useful in supplying magnesium, sulphur and iron.[ They are also one of the few plants that can tolerate, and flourish in, soils rich in poultry droppings.
Controlled Release Fertilisers
When growing in containers or baskets you can use controlled release fertilisers. These gradually dissolve over the growing season ensuring a constant supply of nutrient is available to the plants over the season.
I hope these information will be useful reference to me whenever I am out shopping for fertilizers or when applying fertilizers to my plants or when my plants show sign of ailing.