Loosening or turning the soil to allow more intake of air and water, permitting plenty of room for roots to grow and access nutrients within the soil.


Plants whose life cycle lasts only one year, from seed to blooms to seed. Most vegetables are grown as annuals in Chicago.


Also called “going to seed,” is when a plant flowers and moves toward producing seed. This can occur as a result of hot weather, plant stress or simply that the plant is going into the reproductive stage of its life cycle. For vegetables and herbs, once a plant bolts, it’s at the end of its life cycle, will no longer taste good and should be pulled out.


Early stages of development of a flower or plant growth.


The thick, underground storage organ of a plant. Vegetable crops that grow from bulbs include onions and garlic.

Companion plant

Plants that work well together because they benefit one another, with one plant perhaps attracting a beneficial insect that will prey on a pest insect.


Organic matter such as leaves, lawn clippings, vegetable and fruit scraps, and other plant material that has decayed enough to use as a nutrient dense soil additive and fertilizer.

Cotyledons, or seed leaves

The first leaves a seed produces upon germination. Cotyledons do not generally resemble the leaves of the actual plant, so it’s important to know what they look like before you thin them.


The growing point of a plant where new shoots emerge, at or just below the soil surface.


Varieties of vegetable plants that grow to a compact size, produce a limited amount of fruit all at the same time, then stop growing and die. See also: indeterminate.

Direct sow

To plant seeds outdoors in their final positions, where you would like them to flower or crop. Some vegetables can be transplanted from seedlings, some grow best when sown directly, and a few vegetables can be grown either way.

Extension office

A nationwide collaboration of government and state universities whose mission is to provide information on a variety of topics, including agriculture. Extension offices are great resources for information on local horticulture; the University of Illinois extension website can be found here.


Plant foods used to amend the soil in order to improve soil health and the quality or quantity of plant growth. Organic fertilizers include compost, bat guano, vermicompost, blood and bone meal, kelp and manure.


The point at which a seed sprouts leaves and begins to grow. Germination time is important to consider when timing seed sowing.


To unite the short length of a stem of one plant with the root stock of a different plant in order to have a stronger, healthier plant.


Varieties of vegetable plants that grow and produce fruit until the plants are killed by frost. These varieties will require more extensive support than determinate varieties.


Powdered fungi or bacteria that help legumes such as green beans and peas fix nitrogen, creating a larger yield and reducing the need for fertilizer.


Material placed over soil to control weeds and retain moisture. The best type of mulch for an organic food garden is straw or alfalfa hay (not grass hay containing weed seed).


Nitrogen, phosphorus, and potassium are the three basic nutrients that plants need. These are the numbers you’ll see on a bag of commercial fertilizer – 10-10-10 refers to the ratio of nitrogen, phosphorus, and potassium in the mix. Certain plant problems can be fixed by adjustments to the soil nutrients.

Organic gardening

An approach to gardening that focuses on maintaining and cultivating soil health without the use of synthesized fertilizers, pesticides, or fungicides.

Organic soil

Soil which has not had chemical treatments and is mixed with additional organic material for a number of years. Some commercially available packaged soil mixes are organic, but it’s important to research the manufacturer. A good resource is the Organic Materials Review Institute’s list of manufacturers and products. You can also mix your own organic soil by starting with organic materials such as compost, manure, and rock dust; recipes are commonly available online.


A plant that returns and produces fruit every year. Few vegetable plants are perennials in Chicago, but asparagus and rhubarb are among them, as well as a number of herbs. Many varieties of berries and tree fruit can be grown perennially here.


The measurement of calcium in the soil. Soil with a pH lower than 7.0 is considered acid soil; a pH higher than 7.0 is considered alkaline. Optimal pH for different plants varies, but in general, a pH between 6.0 and 7.0 is advisable for a mixed vegetable garden.

Pinching out

To remove the growing points of plant in order for side-shoots to form.


The transfer of pollen between flowers, usually carried by the wind and insects. If you’re low on wind or insects, pollinating can also be accomplished by hand.

Potting soil

A loose, nutrient dense and light soil mixture designed for use in container gardens. Potting soil is ideal for growing vegetables in containers.


To cut and trim plants in order to remove dead or injured part(s) of the plant(s) – or in the case of tomatoes, removing suckers.

Root crops

Vegetables that grow underground with leaves above the soil, such as radishes, beets, carrots, and potatoes. For root crops, it is especially important to have deep, loose soil they can grow down into (ideally 12-18 inches).


Small plants ready for transplanting into a garden bed, either purchased or started indoors.


A plant that does not need pollen from other plants in order to fertilize.


To drive a stake into the ground to use as support for a plant.


On tomato plants, suckers are shoots that grow in the joint between the plant’s branch and a stem. These can be removed by cutting or pinching them off, allowing the plant to put more energy into fruiting to produce a higher yield.

Tender plants

Plants unable to sustain cold temperatures. Common tender vegetables include tomatoes, eggplants, squash, and cucumbers. Jeanne Nolan refers to these types of plants as heat-loving plants.


The removal of excess seedlings in order to allow more room for growing.


A hand tool similar to a shovel used for digging.


The end-product of using earthworms to break down organic matter, such as vegetable scraps and newspaper.