Complete Container Herb Gardening: Design and Grow Beautiful, Bountiful Herb-Filled Pots

If your garden doesn’t have much space for growing herbs, a container garden might be the answer. I recommend a new book on this topic by western Washington writer, Sue Goetz.

I approached her “Complete Container Herb Gardening” in two ways. First, it is a very basic but detailed guide to using pots to host a significant part of your garden, or even the whole thing. “Growing in any type of container affords the opportunity to plant a garden almost anywhere.” This includes inside a home, on a balcony, or in a small corner of a yard devoted mostly to boisterous activities by children and pets. Hanging baskets or vertical planting walls provide other options.

The second focus of my reading was on the herb plants she recommends. Defining herbs broadly, she include all plants with essential oils and other parts for use in cooking, cleaning, body care, and many treatments for well-being.

Goetz is a teacher at heart, and her lesson plan for this book is well thought out. In addition to how to choose a container, she provides detailed projects that teach how to design, combine, and maintain your plantings. By using various herbs, these plant combinations have benefits beyond their beauty. Even if your goal was only for pretty flowers, you may realize that these primarily foliage plants are also very ornamental, and suddenly you, too, are an herb gardener.

Excerpted from the Spring 2021 issue of the Arboretum Bulletin

growing herbs indoors

I want to grow herbs indoors, especially over the fall and winter. Can you recommend some good books, and tell me how to get started? What’s the minimum temperature for growing them?

One of my favorite general books on growing herbs is by a Seattle gardener and author, Mary Preus, entitled The Northwest Herb Lover’s Handbook (Sasquatch Books, 2000), but there is limited information on growing them indoors. Another book, The Edible Indoor Garden by Peggy Hardigree (St. Martin’s Press, 1980) includes a section on herbs to grow as well. Most of the herb gardening books discuss bringing culinary herbs which have been growing outdoors inside during winter, when it is less possible to grow them outdoors. According to Patrick Lima, author of Herbs: The Complete Gardener’s Guide (Firefly Books, 2001), “a thriving indoor herb garden depends on good sunlight–a sun room, greenhouse or large south-facing window–but many herbs need winter rest. Obvious choices for wintering indoors are tropical herbs or Mediterranean plants–fruit and pineapple sage, scented geranium, rosemary, bay…” The best choices for fresh winter use are basil, parsley, tarragon, oregano, the mints and hardy savories, chives and garlic chives, rosemary, tropical sages, lemon verbena, and scented geranium.

The National Gardening Association has useful information on indoor herb gardens. Here is another article from the same site.
This gardening blog focuses on using recycled containers, such as growing herbs in old dresser drawers (but make sure not to use furniture that may have been painted with lead-based paint!).

This University of Missouri Extension link (now archived) has a useful guide to indoor herb gardening, excerpted below:
“Growing herbs indoors by Kathryn Keeley,MS,Former Horticulture Specialist

In 1652, Nicholas Culpeper wrote The English Physician, which combined the folklore and traditional medicine that surrounded herbal usage during that time. Colonists in North America consulted this book as a medical reference. Herbs served a variety of functions in the pioneer home, including curing illness and disease, dyeing fabric and repelling insects.

Today, consumers are turning to herbs for increased health and vitality, as well as for more domesticated duties such as decorating and cooking. A perfect way to get the taste of summer is by growing herbs indoors during the cold months. Here are a few tips if you’d like to grow your own herb supply:

Light source. Perhaps the greatest challenge when growing herbs indoors is providing them with sufficient sunlight. Herbs do best when grown in a very sunny window that receives between six and eight hours of direct sunlight each day (typically a southern or southwestern exposure). When growing herbs under natural light, be certain to rotate the pot every three to four days to ensure uniform growth of the plant.
If your most convenient window location does not have enough sunlight you can supplement natural lighting with fluorescent light. In general, for every hour of required sunlight expose the plants to two hours of fluorescent light. Herbs grown entirely under fluorescent lights will require between 14 to 16 hours of artificial lighting. Place herb plants no closer than five or six inches and no farther than 15 inches from the light source.
Drainage. Herbs demand good drainage for healthy growth. A potting mix of equal parts sand, commercial potting mix, peat moss and perlite will provide an excellent medium for growing herbs indoors. When potting your herbs, choose clay pots. They are more porous than plastic pots, allowing for better soil drainage.
Temperature. Be certain not to locate your indoor herb garden near a heat source, such as a radiator or heat vent. Herbs prefer temperatures below 70 degrees. If the air is dry in your home, place the herb pots in a tray of stones and keep the tray filled with water just up to the bottom of the pot. Providing ample humidity will promote good herbal growth while keeping the foliage succulent and tasty.
Fertilizer. When grown in containers, most herbs will benefit from occasional feeding with a liquid fertilizer, such as fish emulsion, seaweed or a general-purpose, water-soluble fertilizer. In general, feed herbs every two weeks according to the manufacturer’s instructions. Be certain not to overfeed your herbs. Too much fertilizer is far more likely to damage your herbs than too little.
Herb types and use. Chives, Thyme, Basil, Parsley, Rosemary, Sage, Oregano and Mints all do well indoors. Use them regularly to keep them trimmed back and prevent flowering, which will reduce the plant’s longevity.

sowing herb seeds in July and August

Are late July and early August still a good time to start sowing seeds for basil, parsley, and coriander in Seattle?

According to Winter Gardening in the Maritime Northwest by Binda Colebrook (Sasquatch Books, 1998), you can sow coriander in late August to early September and as long as the winter is not too harsh, you should have success. You may want to keep the plants under cover during winter.

When you sow parsley, Colebrook recommends looking for European varieties which are cold-hardier than the American type. The following article, from the British paper The Guardian (July 1, 2006 issue) discusses summer sowing:
Summer-sown parsley by Sue Stickland

Here is an excerpt:

“Spring-sown parsley often struggles, but sow now and it’s easier to get healthy plants. These should give a good crop right through to autumn, and look as decorative in beds, pots and troughs as they do on the plate.

Sow directly where it is to grow, or into small pots for transplanting, and keep it moist. In steady July temperatures, germination should take a couple of weeks (quicker by half than in spring). Plant out seedlings from pots as soon as they are big enough, and before the ‘tap’ root hits the bottom. This will give stronger, more resilient plants.

The main enemies of spring-sown parsley are aphids and carrot flies. Aphids not only make the leaves unappetising, but carry viral diseases; carrot flies tunnel into the roots, weakening the plant, just as they do with their main vegetable host. When parsley starts to yellow and redden, and plants become stunted, one or other of these pests is usually to blame. July sowings avoid the worst attacks, provided you keep them well away from any ailing plants. Never try to grow this herb in the same spot twice.

For vibrant, deep green leaves, the plant must also have rich soil and plenty of moisture. Add well-rotted manure or garden compost (or a bagged equivalent) to a garden patch, and to the potting compost in deep troughs and pots. Don’t forget them in dry spells – most herbs won’t need watering, but parsley will. When it turns cold, bring pots into a cold frame, greenhouse or other warm, protected spot. These late-sown plants will provide welcome fresh sprigs in winter and early spring.”

Basil is a half-hardy annual, and is best sown into pots in early spring, or directly into the garden in late May. I don’t think you can successfully grow an outdoor fall/winter crop. Mary Preus, author of The Northwest Herb Lover’s Handbook (Sasquatch Books, 2000), suggests potting up plants from your garden in September and moving them indoors. If given the right light and care, you can keep harvesting throughout the winter.

drought-tolerant container planting

Our neighborhood has a small planter area at its entrance. There is no water supply to this area, but a nearby resident is willing to water occasionally. The soil contains much clay. We would like to plant a few drought-tolerant annuals to add color and supplement the more permanent shrubs–such as boxwood–planted in the area. Can you recommend some plant choices? How could we amend the soil to best hold water during the upcoming dry months? Would a commercial product such as “Quench” be of any value, in addition to organic mulches?

I found the following article by Nikki Phipps on GardeningKnowHow.com about drought-tolerant container planting. Here is an excerpt:

“…many plants not only thrive in containers but will tolerate hot, dry conditions as well. Some of these include annuals like marigolds, zinnias, salvia, verbenas, and a variety of daisies. Numerous perennials can be used in a xeriscape container garden such as Artemisia, sedum, lavender, coreopsis, Shasta daisy, liatris, yarrow, coneflower and more. There is even room for herbs and vegetables in the xeriscape container garden. Try growing oregano, sage, rosemary, and thyme. Vegetables actually do quite well in containers, especially the dwarf or bush varieties. There are also numerous ornamental grasses and succulents that perform nicely in containers as well.”

This Brooklyn Botanic Garden’s 2001 article provides a list of drought-tolerant plants for containers.

I had not heard of Quench, but since it is cornstarch-based, it is certainly preferable to the hydrogel and polymer products which are more widely available. I found an article by garden writer Ann Lovejoy in the Seattle P-I (June 3, 2006) about Quench. Here is an excerpt:

With pots and containers, mix dry Quench into the top 12 inches of potting soil in each pot and top off with plain compost. Few roots will penetrate deeper than a foot, so it isn’t very useful down in the depths of really big pots unless you are combining shrubs and perennials.

I would not recommend hydrogels or polymers as a soil amendment. Professor Linda Chalker-Scott of Washington State University has written about these products and their potential hazards. Here is a link to a PDF.

You could consider applying a liquid fertilizer (diluted seaweed-fish emulsion would work) to your containers once every week or two during summer. Here is an excerpt on some general information on container maintenance, from a no longer available Ohio State University Extension article. Excerpt:

“Once planted, watering will be your most frequent maintenance chore, especially if you are growing plants in clay containers. On hot, sunny days small containers may need watering twice. Water completely so that water drains through the drainage hole and runs off. Water early in the day.

“If you incorporated a slow release fertilizer into the potting mix, you may not need to fertilize the rest of the season; some of these fertilizers last up to nine months. You can also use a water-soluble fertilizer and apply it according to the label directions during the season.

“Mulch can be applied over the container mix to conserve moisture and moderate summer temperatures. Apply about one inch deep.

“Depending on the plants you are growing, you will need to deadhead and prune as needed through the season. Monitor frequently for pests such as spider mites. Pests usually build up rapidly in containers.”

vegetables that can tolerate partial shade

What herbs and vegetables grow well in very little sun?

The following is a list of vegetables that can tolerate partial shade. While productions may be greater in the sun, these plants will produce an edible crop when grown in a shady location.

From an article on The Old House Web (no longer available online):

VEGETABLES

Arugula

Beans

Beets

Broccoli

Brussels sprouts

Cabbage

Cauliflower

Celery

Cress

Endive

Kale

Kohlrabi

Leeks

Parsnips

Peas

Potatoes

Radish

Rhubarb

Rutabagas

Salad Burnet

Sorrel

Spinach

Summer Squash

Turnips

HERBS

Garlic

Angelica

Borage

Caraway

Chervil

Coriander

Parsley

Lemon Balm

Lovage

Mint

Tarragon

Thyme

This article (“Best Shade-Tolerant Vegetables”) in Mother Earth News offers more detail about the amount of sun or shade needed.

Remember that most of these plants do not grow in complete shade. Plants will need some morning, evening or filtered sun; a total of two to six hours of direct sun is the minimum.

lilac and elm wood and allelopathy

I have a huge planter to fill but don’t want to buy that much soil so I want to partially fill it with wood. I’m going to plant herbs in it but I wanted to know if the wood I have would make eating the herbs inadvisable. I have roots and branches from a snake bark elm and some large pieces of lilac. None of the wood is treated but I know some wood is poisonous and wasn’t sure about these two.

Before you go ahead with using wood to fill in the planter, another trick
you might try is to put an upended smaller pot inside the large pot, if
the planter is too deep. What you are looking for is a potting medium
with good drainage.

I am not familiar with snakebark elm (there is a snakebark maple, and a
lacebark elm–might it be one of these?) so I can’t give a conclusive
answer about its wood or roots. The phenomenon of plants which are toxic
to other plants is called allelopathy. The most famously allelopathic
tree is the black walnut. Apparently, lilac wood (Syringa vulgaris) has
the ability to raise the phenolics content in the soil, according to a
2004 scientific article (now archived) I found, from the 2nd European Allelopathy Symposium.

To be on the safe side, I would avoid using the lilac and elm wood as
filler in your planter, since there are better options.

You may find the information below useful:

Local gardener Mary Preus’s book, The Northwest Herb Lover’s Handbook
(Sasquatch Books, 2000) offers a recipe for potting soil for herbs grown in containers:

8 quarts compost, earthworm castings and/or composted chicken or steer
manure
4 quarts sphagnum peat moss
4 quarts perlite
4 quarts builder’s sand
1 cup all-purpose fertilizer mix (she has another recipe for this*)
3 tablespoons ground dolomitic limestone

2 pounds fish meal or crab meal
1/2 pound greensand
1/2 pound steamed bonemeal
1 pound rock phosphate
1 pound kelp meal

Virginia CooperativeExtension also has information on soil mixes for growing edible crops in containers:

“A fairly lightweight mix is needed for container gardening. Soil
straight from the garden usually cannot be used in a container because it
is too heavy, unless your garden has sandy loam or sandy soil. Clay soil
consists of extremely small (microscopic) particles. In a container, the
bad qualities of clay are exaggerated. It holds too much moisture when
wet, resulting in too little air for the roots. Also, it pulls away from
the sides of the pot when dry.

“Container medium must be porous in order to support plants, because roots
require both air and water. Packaged potting soil available at local
garden centers is relatively lightweight and may make a good container
medium.

“For a large container garden, the expense of prepackaged or soil- less
mixes may be quite high. Try mixing your own with one part peat moss, one
part garden loam, and one part clean coarse (builder’s) sand, and a
slow-release fertilizer (14-14-14) added according to container size.
Lime may also be needed to bring the pH to around 6.5. In any case, a
soil test is helpful in determining nutrient and pH needs, just as in a
large garden.”

on the difference between marjoram and oregano

I have marjoram and/or oregano growing all over. I like it and use it
as filler, left over from herbs I bought several years ago. But, to
cut them and use for seasoning, I don’t know which is which and they
don’t seem to be so fragrant. Should I just start over and buy new
plants to know what I have? How can I tell the difference between the two plants?

Everytime I get this question (this almost qualifies for a frequently asked
question) I have to look it up again because even the authorities get mixed
up.

Oregano and marjoram are the same genus, Origanum, but different species/hybrids. Marjoram usually refers to Origanum majorana. Marjoram leaves tend to be more gray green in color than oregano, and the leaves are generally smaller. Oregano usually refers to Origanum vulgare. It has a more pungent flavor, while marjoram is sweeter and milder. If you are interested in learning more, this guide from the Herb Society of America goes into great depth on oregano and marjoram.

The short answer to your question is yes, you should start over with new
plants if you want good flavored herbs. You could bring in a sample to the Hyde Herbarium here at the Center for Urban Horticulture, 3501 NE 41st St. Seattle.

parsley: a perennial or a biennial?

Is Italian parsley a perennial or a biennial?

The Sunset Western Garden Book says that parsley (Petroselinum species) is a biennial grown as an annual.

University of Arkansas Extension provides additional information on growing parsley, including the Italian variety, which is Petroselinum neapolitanum, and curly leaf parsley, Petroselinum crispum.

propagating Schisandra fruit vine

How can I propagate the Schisandra fruit vine?

It does not sound like the easiest plant to propagate from seed. Cuttings or layering might be less challenging. The Maine Organic Farmers and Gardeners Association has a guide to growing Schisandra, including propagation information. Here is an excerpt:
“Propagate Schisandra by seed, cuttings or layering. The seeds can be planted in prepared seedbeds 1/4-inch deep in the fall soon after they ripen or indoors in March. Dry seeds need to be soaked overnight. In Herbal Emissaries: Bringing Chinese Herbs to the West, Steven Foster and Yue Chongxi say that in China an acid scarification process is sometimes used, because the seeds have such a hard coat.”

Plants for a Future’s database includes propagation details for Schisandra chinensis:
“Seed: best sown in the autumn in a cold frame. Pre-soak stored seed for 12 hours in warm water and sow in a greenhouse in the spring. Germination can be slow and erratic. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in light shade in the greenhouse for their first 2 years. Plant them out into their permanent positions in early summer.
“Cuttings of half-ripe wood, 5 – 8cm with a heel, August in a frame. Overwinter in the greenhouse and plant out in late spring.
“Layering of long shoots in the autumn.”

Garden Tip #127

Make room for herbs in your garden. Many herbs like rosemary and sage look good during winter, most are edible or medicinal, drought tolerant, and aromatic – what more could you ask for in a plant? Herbs do not have to be planted in a separate garden bed, so go ahead and mix some chives or chervil in with your flowers. Herb enthusiasts may want to join the Herb Society of America. For $50.00 per year members receive two publications and discounts from specialty herb nurseries. Call (440) 256-0514 or visit www.herbsociety.org.