Compiled from the Between the Rows Herb Supplement by Extension Master Gardener Brigitte Coulton, March 2021. Based on original work by Extension Master Gardener Renee Johnson.
Please see the vegetable growing guidance covered in the Between the Rows newsletter that also pertains to growing herbs, including, for example, testing your garden’s soil and drainage, starting plants from seed, crop rotation, and companion planting (see January and February) and on intercropping, container gardening, and best practices to avoid common pest and disease problems (see September and December).
Most herbs are adapted to areas with ample sun, well-drained rocky soils, and dry summers, so growing herbs in Virginia can be challenging. See the information from the University of Georgia Extension on growing herbs in southern gardens. A PowerPoint presentation from the Portsmouth, VA, Extension Office provides useful information on growing herbs in Virginia. See also a publication from Clemson University Extension on growing herbs in areas with generally heavy soils and more humid conditions. For other general information, see the Virginia Cooperative Extension (VCE) publications “Herb Culture and Use” and “Herbs and Spices.”
To increase your success of growing herbs in our area, growing herbs in raised beds and using a gravelly mulch can help improve soil drainage. Drainage may be improved by adding pine bark, wood chips, pea gravel, sand, poultry grit, or coarse compost (such as pistachio shells) to soils. Herbs prefer a mostly neutral soil with a pH of 6.5 to 7.5. Consider if you need a soil test. In general, add lime if pH falls below 6.5, and add sulfur if pH is greater than 7.3.
As with most plants, “right plant/right place” applies to growing herbs. When planning an herb garden, remember that most herbs need at least six hours of sun daily. Few herbs prefer partial shade or shade. Some shade-tolerant herbs include: anise hyssop, angelica, bay, comfrey, chervil, dill, lemon balm, parsley, pennyroyal, mints, shiso/perilla, spicebush, sweet woodruff, and some varieties of ginger.
Also, when choosing plants, try to buy from suppliers that may be more knowledgeable about which cultivars are more tolerant of our area’s climate and conditions. Dill, for example, tends to die out or die down when our summers get hot, thriving instead in spring and fall. Also important: herbs, such as mints, lemon balm, lemongrass, and horseradish, may spread aggressively and may need to be grown in a separate area or container.
Refer to VCE’s Herb Culture and Use publication for guidance on herb cultivation. Specific tips for most common herbs can be found in this herb directory from the University of Illinois Extension. For chili peppers, some recommend pinching out early flower buds and small fruits to produce stronger, more prolific plants (see Maryland Extension info). Herbs may be propagated from seed, stem cuttings, division, and layering. Most annual herbs are grown from seeds (see this MGNV presentation on seed starting). Parsley, though a biennial plant that will regrow after a harsh winter, should be treated as an annual. In its second year its growth goes into making flowers and ultimately seeds, at the expense of leaves and flavor. See this useful herb planting schedule. For information on propagation, see VCE’s publications on Plant Propagation from Seed and Propagation by Cuttings, Layering and Division.
There are many design options to choose from when planning an herb garden, including fragrance gardens, potpourri gardens, Shakespeare gardens, and herb gardens for salads, teas, or plant dyes. A current favorite is the herb spiral, a vertical garden design that allows plants to be stacked to maximize space and provides a high point for sun-loving plants (e.g., rosemary, sage, and thyme) while plants that are more tolerant to shade and moister soil conditions can be planted within the garden’s wider base. This Oklahoma Extension video provides detailed instructions on building an herb spiral, with a discussion of some of its general benefits and plant placement.
Homegrown Pantry by Barbara Pleasant was reviewed by Extension Master Gardener Susan Wilhelm on the MGNV website: “Whether you grow vegetables, herbs, or fruits and berries, Homegrown Pantry is a useful resource for gardeners (even those with limited space) to get the most from their garden by making informed choices about what and how much to plant and the best preservation techniques.”
If you are interested in growing medicinal herbs, this presentation on the MGNV website from June 2020 on Growing a Medicinal Herb Garden is specifically for the Northern Virginia area.
Insects & Disease
Generally, herbs have relatively few insect and disease pests as long as you follow good cultivation practices. Companion planting—planting herbs alongside vegetables—may help minimize pest and disease issues in your garden. Avoid pairing strong aromatic herbs with cucumbers, and separate dill and carrots, and rue and basil. See also this info on companion planting from Cornell University Extension.
Watering & Humidity
Most herbs should be watered thoroughly; however, the soil should be allowed to dry out somewhat before watering again. Plants also should be watered earlier in the day to allow the plant’s leaves to dry before nightfall.
Few herbs will grow in moist-to-wet soils. Some exceptions include monarda, comfrey, lemongrass, mints, parsley; however, some tender annuals may require more moist conditions. Some herbs (French tarragon, chervil, cilantro, cumin, and chamomile) are particularly susceptible to humidity and may grow best in containers under more controlled conditions. Other herbs that generally grow well in containers include basil, chives, coriander, oregano, parsley, rosemary, and sage.
Pruning & Harvesting
Herbs need to be regularly and generously pruned or harvested to promote vigorous, well-shaped, sturdy growth but also sustained regrowth. In some cases, up to 50-75% of a plant’s current season’s growth can be harvested at one time. Begin harvesting when the plant has enough foliage to maintain growth.
As a general rule, harvest herbs when the oils responsible for their flavor and aroma are at their peak. Proper timing, however, will depend on the plant part you are harvesting and its intended use (e.g., flower, leaf, root, seed).
Spring To-Do List
- Pinch out the tips of new plants to force them to branch and become full.
- Test soil drainage and consider adding gravelly amendments, such as pine bark, wood chips, pea gravel, sand, poultry grit, or other coarse compost materials.
- Determine if you need a soil test.
- Depending on the weather and herb, continue to grow plants from seed indoors.
- Start pepper plants from seed indoors but wait to plant outside until temperatures reach about 70ºF (see this info on growing peppers).
- Bring out perennials that were over wintered indoors.
- As temperatures rise, harden off plants grown from seed indoors (see this info on hardening off).
- Divide/plant horseradish crowns, preferably in pots since plant can tend to spread (see this info on horseradish).
- Less heat tolerant herbs, such as cilantro and dill, may be planted in early spring.
- Some herbs may be transplanted outdoors (or directly sown) in early-late spring: bee balm, catnip, chamomile, chervil, chives, fennel, lemon balm, lovage, marjoram, mint, parsley, rosemary, sage, thyme (check growing schedules).
- Wait until well after the last spring frost to transplant or sow tender annuals outdoors, such as basil (see this info on basil) and other warm weather herbs; these require a soil temperature of 60-70ºF.
- Propagate by dividing and layering hardy perennial herbs that may have survived the winter, such as chives, hyssop, lavender, lemon balm, mints, oregano, sage, thyme, tarragon, and winter savory (see VCE’s info on propagation by layering).
- Some hardy perennials may be dug up and divided in the spring to generate new plants.
- Harvest garlic scapes while still tender.
Summer To-Do List
- Deadhead herbs by pinching or snipping florets or seed heads off the top of the plant to prevent bolting and going to seed.
- Mulch base of plant to speed growth, conserve water, and reduce weeds.
- Refrain from overwatering plants as many herbs cannot tolerate overly damp soils and require good drainage.
- Regularly inspect and monitor herbs for common pests, such as whiteflies, spider mites, aphids, mealybugs, scale insects, and ant thrips.
- Discontinue some less heat tolerant herbs, such as cilantro and dill (pull spent plants).
- Continue to direct sow basil every 2-3 weeks for continuous replacement.
- Continue to divide runner herbs, such as mint, bee balm, and artemisia.
- Harvest and prune herbs to promote vigorous, well-shaped, sturdy growth, and to stimulate additional regrowth.
- Harvest fresh leaves as soon as the plant has enough foliage to maintain growth and before they flower (see more from Maryland Extension).
- Harvest garlic when about half the leaves die back/yellow; dry and cure before storing (see this garlic production info).
- Some leafy herbs, such as mints and lemon balm, will be starting to reach their peak and will also be ready for harvest.
- Harvest and store over abundant herb supplies through drying, freezing, and preserving herbs; NC State Extension provides detailed information on harvesting and storing herbs for future use.
Fall To-Do List
- Aggressively prune back some herb plants (basil, sage, oregano, marjoram, thyme, parsley) to try to get a bit of last regrowth before the first freeze.
- Remove spent/diseased plant material.
- Mulch mint containers and other overwintering hardier herbs (sage, tarragon, rosemary, bay); protect plants by keeping them out of windy, open areas.
- Collect and store seed from spent plants to sow next year.
- Prepare herbs to maximize their chance of winter survival (including providing extra protection and bringing in some tender herbs to overwinter or allow to go dormant indoors).
- Clean up and put herb garden to bed.
- Prepare new planting beds for next year.
- Now is also a good time to review this year’s successes and failures.
- Plant garlic, onion, and shallots in mid-late October (see planting instructions for alliums here).
- Plant seed outdoors for some cold-tolerant herbs (such as arugula, mints, cilantro, dill, parsley) under protective cover for a late season continued harvest or for next spring.
- Divide and propagate herbs for next year either by separating runner herbs or through stem and root cuttings.
- Grow some herbs indoors for winter use, such as oregano, parsley, dill, and chives.
- Herbs grown in containers can be brought inside in winter (e.g., bush basil, sage, winter savory, parsley, chives and some oregano and thyme varieties) but will need sunlight from a south- or west-facing window. Make sure not to overwater! Let the soil fully dry out before watering deeply.
- Perennial herbs may be planted in fall (if hardy): thyme, rosemary.
- Harvest late season herbs and peppers.
- Harvest and dry herbs, such as sage, lavender, bay, rosemary, and Vietnamese coriander, as well as other types of herbs for teas (mints and chamomile).
- Harvest horseradish once soil temperatures cool in late-fall or winter (or early spring).
- Keep a close watch on saffron crocus flowers to harvest the orange stigmas at their peak.
- Collect pruned branches, such as rosemary and lavender, for use in making an herbal wreath or other seasonal projects, such as potpourri or herb jellies.
Winter To-Do List
- Plan your next herb garden!
- Inventory your remaining stored and saved herb seeds from last year.
- Buy seeds and order starter plants from your favorite garden catalogs.
- Order horseradish crowns or try to grow using a root from the supermarket.
- Store newly purchased seeds in a cool, dry, and dark place.
- Collect plastic milk or soda containers to use later as cloches to protect tender plants from cooler temperatures after transplanting.
- Continue to care for any less hardy perennial herb plants that you may have brought in to over winter and any annual herb plants you are growing indoors; make sure your plants are getting enough sunlight and not too much water.
- Prepare to start new annual and perennial herb plants from seed indoors, with the help of heating mats/lights or a warm sunny spot in your home (refer to planting guides for our area for specific planting dates).
- Start sprouting indoors rooting herbs, such as ginger and turmeric.
- Plant indoors in February-March: bergamot, catnip, chervil, chives, dill, fennel, lavender, lemon balm, lovage, marjoram, mint, oregano, parsley, rosemary, sage, and thyme. Information on growing herbs indoors is available from the Penn State Extension.
- Depending on the harshness of the winter and the location of the herbs in your garden, you may be able to harvest from some perennial herbs left to winter in the garden, including rosemary, thyme, oregano.