All plants need three major elements for proper growth – nitrogen, phosphorus, and potash. The best growth is impossible if your soil does not contain them in the right quantities.
This is why soil pH testing is needed. Soil testing lets you supply the soil with the missing nutrients in the right quantity.

Nitrogen stimulates growth; phosphorus makes better flowers, fruits, and seeds; potash aids the roots, stems, and stalks; counteracts brittle growth. It also intensifies the color and fragrance of flowers and is greatly needed in summer and fall.
Soil Changes Every Year
Growing plants absorb these elements, removing them from the soil. Your garden soil fertility is very different this spring from last summer.
All your plants take food out of the soil like a spendthrift takes money out of the bank. An acre of tomatoes takes a lot of fertilizer out of the soil!

How can you know what fertilizers must be added this spring to bring the soil back to its ideal fertility level?
How can you know what kind of fertilizer to use? And how much?
How can you know whether your soil is sweet or acidic, and how to correct it?
Soil testing is the only answer. Vegetables, flowers, fruits, evergreens, shrubs, roses, and lawns must have a balanced diet to do their best. Practically every garden soil is out of balance unless it is tested.
Test Soil pH Yourself
For a home, soil testing kits provide home gardeners with an easy, accurate way of determining the fertilizer requirements of any soil.

These Kits will show just how much and what kind of plant food is needed in every part of your garden and grounds and save money, too.
Gardeners often find they use too much of some kind, which might do more harm than good — not enough of others.
These testing kits, complete with everything needed for years of gardening and easy-to-follow directions, show you directly what plant nutrients must be added to your soil for whatever you want to grow.

They also test for pH (acidity or alkalinity) and tell you how to make your soil just the right pH for the particular plants you want to grow, such as lime-loving lilacs and clematis vines, as well as those needing acid soil, such as azaleas, rhododendrons, blueberries, etc.
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