Today's post will cover fertilizer. This is something very tricky. On one end of the spectrum, you can have soil with too few nutrients and thus, plants that grow very poorly. On the other hand, if you use too much, you can get your soil too 'hot.' This is a very technical term that my mother uses to describe the infamous horse manure incident. Good ole' Dad was sure that his pile of horse manure had sat and composted for enough years that is was ready for garden use. Mom was not so convinced, but Dad persisted. The composted horse manure was incorporated into the soil of one flower bed, and the plants literally burned to death from the heat of strong, not-yet-fully composted horse crap.
It was not pretty.
So, how to choose fertilizers...
The three basic nutrients that plants need are nitrogen (N), phosphorus (P) and potassium (K). When buying fertilizers, the nutrient content will be displayed in numeric form in the N, P, K order. For example, if a bag reads 6-12-0, the contents contain 6% nitrogen, 12% phosphorus, and no potassium. If you are unsure (like me) about what nutrients your garden plot needs, you can have a soil test done. As a general rule, nitrogen is usually the most depleted nutrient. So, if you are not up for soiling testing this year, you can use the chart below from USU Extension and make a good guess about your nitrogen needs based on what you are planting. That is my current plan of action. Time will tell if it was a good plan or not...
|Ornamentals||Low: xeriscapes, natural areas||0 to 1 pound of nitrogen/1000 sq ft|
|Intermediate: standard landscapes||1 to 2 pounds of nitrogen/1000 sq ft|
|High: flower beds, new landscapes||2 to 4 pounds of nitrogen/1000 sq ft|
|Turf*||Low maintenance||0 to 1 pound of nitrogen/1000 sq ft|
|Intermediate maintenance||2 to 3 pounds of nitrogen/1000 sq ft|
|High maintenance||4 to 6 pounds of nitrogen/1000 sq ft|
|Vegetables**||Low: peas, beans||1 to 2 pounds of nitrogen/1000 sq ft|
|Intermediate: asparagus, beet, carrot, melon, cauliflower, broccoli, brussels sprouts, celery, pepper, tomato, lettuce, radish, spinach, turnip, squash, pumpkins||2 to 3 pounds of nitrogen/1000 sq ft|
|High: onion, sweet corn, potato||4 to 6 pounds of nitrogen/1000 sq ft|
For a more in-depth look, head on over to this USU Fact Sheet or this Oregon State Fact Sheet that both talk about fertilization.