Nitrogen is most important in plants for vegetative growth and chlorophyll production, which of course is what makes plants green.
If the older leaves are thin, small and pale, and the plant develops very woody stems then the plant may require nitrogen. Left uncorrected, the problem spreads to the fruit which becomes spiny, deformed and short.
To correct a nitrogen deficiency
- add composted manure
- plant with peas and beans to fix nitrogen into the soil from the atmosphere
Small yellowish spots on the leaves that get bigger until only the leaf veins are left green may indicate too much nitrogen present. In this case you will see initially see thick strong stems with rich green curled leaves that grow closely spaced on them, along with many side shoots and tendrils.
Too much nitrogen can be corrected by
- heavy irrigation
- keeping the plants cool in order to reduce transpiration
- plant heavy feeding plants like lettuce
Soil testing is an important activity for a successful garden. Soil stewardship is an ongoing process, where you test and amend, grow some stuff, then test, amend and grow some stuff….and so on. Focus on building soil tilth so it can really hold and make available to the plants all the important nutrients. You do this in part by adding compost, manure, rock dust, bone meal, kelp & fish emulsions. Read this article series to learn more about each of the 13 key nutrients for your garden.