WHERE IT ALL BEGINS: THE SOIL - Growing Chinese Vegetables in Your Own Backyard - page 212

SOME COMMON ORGANIC SOURCES OF NUTRIENTS
Nitrogen is not a difficult nutrient to obtain. If you don't use a blended fertilizer, you
can buy large sacks of cottonseed meal, which is probably the least expensive source, or
small, expensive sacks of dried blood. Fish emulsion and fish-and-seaweed fertilizers
supply nitrogen. Rabbit manure is also high in nitrogen, so much so that some garden-
ers keep a pet rabbit just for the fertilizer it produces. Chicken manure contains so much
nitrogen it can burn plants, so don't use it unless composted.
Too much nitrogen is harmful. It produces weak growth that invites insects, and it
can give you all leaves with no melons or cucumbers. As long as you use organic fer-
tilizers, or organic sources of nitrogen, it's unlikely that you'll apply too much; the soil
bacteria must work on organic sources to convert it into a form the plant can utilize,
and they usually maintain a good balance. If, on the other hand, you use synthetic fer-
tilizers, it is possible to overdose. Synthetic forms of nitrogen are also easily washed
away by rain (and if used in containers, by watering). If you use synthetic fertilizers,
never exceed the recommended rates for application; it's safer to give smaller amounts
more frequently.
Caution: After applying nitrogen sources, or fertilizer containing nitrogen, don't use
lime or wood ashes for three or four weeks. You'll start a chemical reaction that causes
nitrogen to evaporate. Conversely, don't spread fertilizer right after applying lime or
wood ashes.