How to Test Your Soil
To have a successful garden, test your soil and amend it if necessary to create the best possible growing environment for plants. Testing your soil means you determine the pH level and nutrient content. Both are important factors in how well your garden grows.
Importance of pH levels and nutrients
Too much of this nutrient or too little of that, and you have problems. Just as humans need the right balance of nutrients for good health, so do plants. For example, when tomatoes grow in soil that’s deficient in calcium; they develop blossom-end rot. Sometimes, too much of a nutrient is detrimental: Excessive nitrogen causes lots of leaf growth (such as clematis or peppers) but few flowers or fruits.
The right pH enables plants to use nutrients from the soil. Soil is rated on a pH scale, with a pH of 1 being most acidic and a pH of 14 being most alkaline. If your soil's pH isn't within a suitable range, plants can't take up nutrients — like phosphorus and potassium — even if they're present in the soil in high amounts. On the other hand, if the pH is too low, the solubility of certain minerals, such as manganese, may increase to toxic levels.
Most vegetables and ornamentals grow well in a slightly acidic soil with a pH between 6 and 7.
Soil-testing methods
The only way to find out whether your soil will be to your plant's liking is to test it. Don't worry; analyzing your soil isn't complicated, and you don't need a lab coat. Here are two ways that you can test your soil:
Use a do-it-yourself kit: This basic pH test measures your soil's acidity and alkalinity and sometimes major nutrient content. Buy a kit at a nursery, follow the instructions, and voilà — you know your soil's pH. However, the test gives you only a rough picture of the pH and nutrient levels in your soil. You may want to know more about your soil.
Have a soil lab do a test for you: A complete soil test is a good investment because a soil lab can thoroughly analyze your soil.
Here's what you can find out from a soil lab's test in addition to the pH level:
Your soil's nutrient content: If you know your soil's nutrient content, you can determine how much and what kind of fertilizer to use. In fact, many soil tests tell you exactly how much fertilizer to add.
Soil problems that are specific to your geographic region: A soil test may help you identify local problems. The soil lab should then give you a recommendation for a type and amount of fertilizer to add to your soil. For example, in dry-summer areas, you may have salty soil; the remedy is to add gypsum, a readily available mineral soil additive.
Fall is a good time to test soil because labs aren't as busy. It's also a good time to add many amendments (materials that improve your soil's fertility and workability) to your soil because they break down slowly.
To prepare a soil sample to use with a do-it-yourself kit or to send to a soil lab, follow these steps:
Fill a cup with soil from the top 4 to 6 inches of soil from your vegetable garden, and then place the soil in a plastic bag.
Dig six to eight similar samples from different parts of your plot.
Mix all the cups of soil together; place two cups of the combined soil in a plastic bag — that's your soil sample.
After you've collected your sample, consult the instructions from your soil test kit or the testing lab.
Gardening Glossary
annuals
Plants that complete their entire life cycle within one growing season. The plant germinates from seed, grows and blooms, and then produces seed and dies.
Gardening Glossary
biennials
A plant that take two growing seasons to complete its life cycle. It germinates and grows leaves and stems in the first year; produces flowers and fruit (seed) in the second, and then dies.
Gardening Glossary
bolt
When a plant flowers or produces seed prematurely.
Gardening Glossary
cold frame
A wooden or concrete block box in which you can grow plants or hold dormant during the cold winter months.
Gardening Glossary
cole crops
A family of vegetables, including broccoli, cabbage, cauliflower, kale, and Brussels sprouts. They thrive in cooler weather.
Gardening Glossary
complete fertilizer
Any fertilizer that contains all three of the primary nutrients, N-P-K (nitrogen, phosphorus, potassium). Phrase is based on regulations governing the fertilizer industry. Does not mean that the fertilizer literally contains everything a plant needs to thrive.
Gardening Glossary
deadheading
The practice of pinching or cutting off spent flowers
Gardening Glossary
evaporative-pad humidifier
A humidifier in which fans blow across a moisture-laden pad that sits in a reservoir of water.
Gardening Glossary
harden off
The process of acclimating plants grown indoors gradually to the brighter light and cooler temperatures of the outside world.
Gardening Glossary
hardiness
The ability of a plant to survive is called its hardiness.
Gardening Glossary
humus
A stable end product of organic-matter decomposition that's believed to increase microbial activity in soil, improve soil structure, and enhance the root development of plants.
Gardening Glossary
Bacillus thuringiensis Bt
An effective bacteria that attacks only the larvae of caterpillar family insects. It is safe to other insects, animals, and humans.
Gardening Glossary
macronutrients
Mineral nutrients that plants need in the largest quantities: nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.
Gardening Glossary
mulch
Organic or inorganic material placed over the surface of soil, usually directly over the root zone of growing plants. Used to conserve moisture, kill weed seedlings, modify soil temperature, provide attractive covering to garden beds.
Gardening Glossary
organic matter
Once-living stuff like compost, sawdust, animal manure, ground bark, grass clippings, and leaf mold (composted tree leaves). Used to enrich soil and improve soil texture.
Gardening Glossary
perennials
Any plant with a life cycle of three or more years. Herbaceous (non-woody) perennials include flowering plants and herbs, mainly. Woody perennials include trees and shrubs. Longevity depends on the plant and growing conditions.
Gardening Glossary
pH
The measure of soil's acidity. Soil with low pH means it's too acidic; soil with high pH means it's alkaline. Most plants grow best in soil with a pH value between 6.5 and 7.2. Neutral soils measure 7.
Gardening Glossary
photosynthesis
The process through which plants take nutrients from the air and from the water in the soil to produce sugars that fuels the plant's growth.
Gardening Glossary
primary nutrients
Nitrogen, phosphorous, and potassium are the three nutrients plants need in the largest quantities.
Gardening Glossary
root crops
Plants with edible underground roots such as onions, carrots, beets, potatoes, turnips. Most root crops are cold-weather crops.
Gardening Glossary
self-blanching
A type of cauliflower with leaves that naturally curl over the head and exclude light. Requires cool temperatures for leaves to curl effectively.
Gardening Glossary
sets
Small onion bulbs, about 1/2-inch wide, that were started from seed the previous year. Grow onion sets with the pointy end up.
Gardening Glossary
side-dressing
The act of adding a small amount of fertilizer around or "on the side" of plants after they're growing.
Gardening Glossary
succession planting
Planting small, 2-to-4-foot patches of plants every two weeks throughout the growing season so that you can harvest a crop over an extended period of time.
Gardening Glossary
thinning
The act of cutting the least robust seedlings in your garden to give the healthier plants more room to grow.
Gardening Glossary
vining crops
Crops that grow on vines, such as cucumbers, melons, pumpkins, and winter squash. They usually require support (staking, trellising, etc.) to keep them off the ground.
