Gardening Tip: What Kind of Fertilizer Should I Use? (Part 1)

Vegetable bounty

Courtesy of Steele County Master Gardeners

I used to go to the big box stores and browse the fertilizer aisle looking for the one that “instantly turns your lawn green” or “promotes fabulously spectacular blooms” or “produces state-fair winning veggies.”  Marketing is a seductive thing.

I knew those three little numbers, 00-00-00, meant something, but left their interpretation up to the professionals.  Turns out, those numbers–what we call N-P-K–are pretty important.  They reflect the key nutrients that soil needs to do its job of making things grow.

In a perfect world, our soils would contain every nutrient in the right proportion to grow whatever we wanted to grow.  And all soils would be the same.  But we live in the Phoenix desert where our typically alkaline soils lack sufficient quantities of nitrogen.

Fortunately, many of our native and desert-adapted xeriscape plants are actually “nitrogen-fixing”–that is, through a  highly efficient chemical process, they produce the nitrogen they need to thrive.  Most legumes, the bean- or pod-producing plants, are excellent nitrogen fixers and include desert favorites:  mesquite, palo verde, ironwood, acacia, senna, and many more.

But where native and desert-adapted plants require no fertilizer, non-native plants need nitrogen and other nutrients just to have a fighting chance at thriving here in our desert gardens.   Turf grasses, roses, citrus, and most other edibles need extra help in the form of fertilizer.  And that’s where N-P-K, or nitrogen-phosphorus-potassium, come in.

Coming next…part 2, the demystification of fertilizer!

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