Herbs arouse kids’ curiosity and interest because they thoroughly engage the senses. What better motivator for student investigations than plants that feel cool, smell great, and can turn mere tomatoes into pizza sauce? Their life stories, it turns out, are fascinating too. After all, these humble plants were early humans’ first medicines, food preservatives, and cosmetics. And that’s just the beginning.
The word “herb” conjures up visions of soothing teas or the green flecks in spaghetti sauce, but just what is a herb? Some people define it as any plant or plant part used as an ingredient for flavor, fragrance, or healing. Spices, it seems, could fit the same bill. Here’s the difference: Herbs are usually defined as plants of temperate climates whose leaves are harvested for use. Spices, on the other hand, tend to be of tropical origin; we use their roots (ginger), fruits (vanilla pods), flowers (cloves), seeds (pepper), or bark (cinnamon). They both differ from other plants in that they contain some active ingredient that is useful to us. But the real role of these adaptations is to help a plant survive in its environment — that is, to defend against being eaten!
These aromatic plants can be a fascinating focus for a growing classroom. They’re easy to raise and have a multitude of uses. Many also offer sustenance to pollinators. Consider using a herb garden to stimulate senses and investigations, bring literature to life, or inspire craft projects. It can also become a lens for studying people/plant connections in different historical eras or regions.
If you don’t have a herb plot in your schoolyard, consider raising them in outdoor containers or window boxes, or even in the classroom under lights or on windowsills. Select from the following materials accordingly.
gardening tools (forks, shovels, rakes)
herb seeds, plants, or plant parts (see Herb Growing Chart, below)
large containers with drainage holes
seed-starting containers, soilless planting mix
PLAN THE VISION
Wherever you’re raising herbs — outdoors in the garden or containers, or in the classroom — you and your students should consider what role you want them to play. Do you imagine mingling the fragrant plants with vegetables and flowers or creating separate bed or container just for herbs? Do you envision planting a medley of herbs to stimulate visitors’ senses? Are you drawn to having a special theme for your herb planting? Here are a few thematic ideas to spark your thinking:
Herbal vinegar (or salad dressing) – Good plants for these products include tarragon, chives, basil, dill, rosemary, thyme, and lemon balm.
Colonial herbs – Students can have fun learning how herbs were used in “olden” times. For instance, rosemary was believed to calm naughty children and sage was used to color gray hair! Thyme, oregano, parsley, and savory might also be found in the Colonial garden.
Spaghetti herbs – Consider raising culinary herbs necessary for this children’s favorite: basil, oregano, parsley, garlic. (Fennel imparts a great flavor, too!)
Herbal teas – Students may want to dry, bag, and sell their own herb teas, or simply enjoy drinking them. Chamomile, lemon balm, peppermint, and spearmint are good (and safe) candidates.
Peter Rabbit herb garden – Inspired by this favorite story, your students might grow some of the herbs it mentions mint, rosemary, sage, hyssop, chamomile, tansy, lavender, lemon balm.
Container herbs – If you plan to raise herbs in containers, you might try these easy-to-grow plants: thymes, mints, parsley, basils, sage, marjoram, oregano.
PREPARE THE SOIL
Most herb plants require similar growing conditions: a minimum of six hours of sunlight per day and moderately rich soil with good drainage. To improve the soil structure and drainage, your students should use garden forks or shovels to loosen the soil to a depth of 8 to 12 inches before planting. If you are planting in an area with nutrient-poor, dry, heavy, or poorly-drained soil, add some organic matter, such as compost, before planting. Rake the soil to form a fine, even bed, which is particularly important if you’re growing herbs from seed.
PLANT SEEDS, PLANTS, OR PARTS
Herbs may be annuals, started from seed each year, as is basil; biennials, requiring two seasons of growth, as does parsley; or perennials, which grow back year after year, like thyme. Generally, you should plant annual and biennial herbs from seed directly in the garden or in containers indoors (to transplant), or buy seedlings. (Your students can save the seed produced by their herb plants for next year’s crop.) You’ll want to buy or get donations of perennial herb plants or propagate them from cuttings or divisions. The Herb Growing Chart, below, highlights the best ways to start different herbs.
Starting from seed – If you want to get a jump on the season, you can start herb seeds indoors under lights or on sunny windowsills and later transplant them to the garden. Use the same types of containers and soilless potting mix that you would use for other indoor seedlings. To encourage healthy seedlings, keep the soil mix uniformly moist until seeds germinate, keep lights 3 to 6 inches above the plants, and water seedlings thoroughly when the mix is dry to the touch. Herb seeds tend to be small, so whether you’re starting them indoors or in the garden, you’ll plant them fairly shallowly (see seed packets for planting depths).
Before you move seedlings outdoors, “harden” them off to get them accustomed to harsher outdoor conditions. Do this by setting them outside for progressively longer periods each day, starting with a few hours and increasing to a full day over the course of a week or so.
Starting from plants or plant parts – You can purchase many herbs from nurseries as young plants, or dig up shoots or sections of mature perennial plants in the spring. Some herbs can also be started from stem cuttings. To do this, snip healthy stems 3 to 6 inches from the growing tip. Remove leaves from the lower half of the cutting and plant the cutting in a soilless mix indoors or in moist sand in a shady outdoor area. Water it gently and cover the container with a plastic bag until new top growth appears. Keep cuttings out of the direct sun so they don’t overheat in their plastic-bag “greenhouse.”
How you lay out your planting will depend on the plants you choose and on your theme. Herbs, like most plants, stay healthier if there’s good air circulation, so space them to allow for the mature size of each plant. (Catalogs, seed packets, and nursery containers give spacing requirements.)
You can harvest most herbs continually as soon as the plant has enough foliage to sustain growth. Harvest herbs grown for seeds, such as dill, caraway, and coriander, as the fruits change color from green to brown or gray but before they scatter to the ground. If students want to dry herbs to use or sell as cooking ingredients, they should spread them in a single layer on trays or screens, or hang them in bundles using rubber bands to hold the stems together. Place the herbs in a dark, well-ventilated place until they are completely dry. Store them in the dark in airtight containers.