Declare your variable in the beginning of your script if you know you're gonna test it later. Don't give it a value at this point. A declared variable that has not been assigned a value will have the value 'null'. Use the === compare operator to check whether the variable is really boolean false. The == operator is not reliable as a value of 0 will also evaluate to false. (Basically, the === asks whether variable are of same value AND datatype!).
Nitrogen Fixation. Nitrogen fixation refers to the conversion of atmospheric nitrogen gas (N 2 ) into a form usable by plants and other organisms. Nitrogen fixation is conducted by a variety of bacteria, both as free-living organisms and in symbiotic association with plants. Because it is the principal source of the nitrogen in the soil, nitrogen that plants need to grow, nitrogen fixation is one of the most important biochemical processes on Earth.
If you were sneaky like me during winter you may have thought to sow lupin and mustard in tidy rows next to slow growing brassicas like cabbage, kale and broccoli. The nitrogen fixing takes place while your brassica crops are growing which helps to grow decent heads rather than all leaves. A green manure crop is a perfect companion mix for those veggies; especially if you donât have the space to put your whole garden to bed over the colder months.