Container Gardens - Growing Herbs

Grow Your Own Fresh Herbs - Container Gardening

More recently as I teach Container Garden classes I'm asked specifically about growing herbs.  In particular small urban patio gardens and families with small children seem to enjoy this activity. I am an avid consumer of fresh, home grown herbs! Photo of harvest of mint, dill, parsley! Herb container gardening is a great way for new gardeners to dig in. There is a great satisfaction in serving delights from your garden. Plus the fragrance from herbs is wonderful. There are many herbs that I always grow in container (aka mint!) This year I'm putting more herbs and veggies in containers to make it easier to access from my kitchen! Planning container gardens is one of the many tasks on my Spring to-do list for my cold climate garden. 

There are many decisions that must be made for a container garden including container selection, soil selection, available light, and care (water, fertilizer). In addition having a plan for materials and support of the containers - for example if you will be gardening on a deck or porch where will you get water, store soil, and does the deck bear the weight? These decisions and tips are covered in Container Garden Basics (blog link coming.) There are some nuances of container gardening just for herbs with a heavy emphasis on plant selection. Please read on...

What not to do! Baskets! Source: Daily Mail

CONTAINER: Almost anything will work as long as there is good drainage. Drainage defined as size of hole in the bottom relative to the size of the container (bigger containers need more or larger holes.) You can even grow corn in a container if it's sized correctly. 

• Type: There are really cute and decorative herb container garden pictures all over the internet. Don't fall for the cute baskets or metal tubs for your herb container garden. While these herb baskets look great - they may be short lived. For the former - the baskets rot and do not last well. For the latter, the metal containers get too hot and rust may be an issue.  I stick with terra cotta or plastic containers. 
• Size: Herbs do not generally have extensive root systems, so smaller containers work relative to annuals and other plants. However, since containers dry out, with smaller containers your watering regime will be more extensive. In some cases I have to water twice a day when it's really hot outside (and I live in Chicago!) My rule of thumb - use the largest pot possible and combined 2+ plants rather than using several smaller pots. Self watering containers also work well for herbs like parsley, chives, and mint that like consistent moisture levels. General rule of thumb - 1 gallon pot space or 8" for every plant to grow in a container (see listing below.)
• Transplanting: You can start herbs in smaller pots and then move them up as they grow. This is a great idea if you have seedlings as small seedlings in very large pots do not do well (too much water) Some herbs will quickly outgrow the container without diligent harvest. Basil for example can get over 2.5 feet tall in no time. 

SOIL & FERTILIZER:  Potting soil you get at the garden center is perfect. Check to see if it has a slow release fertilizer mixed in. If not, add the recommended amounts of fertilizer. Don't worry about fertilizing for flowers - for herbs it's all about the leaves! Some herbs like Thyme and Oregano, don't need fertilizer. I practically neglect mine (other than harvesting) and these two do just fine.  Plan to apply regular fertilizer to your containers. Frequent watering washes out the nutrients so regular 1/2 strength fertilizer every 3 weeks works well. 

LIGHT:  Most herbs need full sun - that's at least 6 hours a day. However some do well with only 4 hours. Many herbs are Mediterranean in origins so think hot and not so much water. If they do not get this much light they get leggy (long stems and not enough leaves.) I'm not 100% certain but I think:

- Mediterranean/Asian in origin include: Celery, Dill, Chives, Mustard, Sage, Tarragon, Marjoram

- Native North America include: Salvia, Beebalm, Nasturtium, Culantro

Keep in mind, in direct and extended sunlight, many containers get warm, or even hot. Too hot. That bakes the roots and will kill your herbs. So some shading in the afternoon can be very beneficial. Feel the side of your containers to see if they are getting too hot - don't worry, they are easy to move a few feet to get out of or into the sun!  I saw one urban herb garden along a fence line between buildings. It didn't get much too much  light, the plants needed pruning to keep growth going.

SELECTING HERBS / CONTAINER PLANS:  For starters, grow what you will use or what has a fragrance you adore! One year I put in Borage and Rue because they looked interesting - but I rarely cooked with them. I tried Celeriac and was pleasantly surprised. Tried fennel and was disappointed but reminded myself I don't like to eat it that much. I like having Sage and Rosemary on the patio because they smell so great. Basil, in multiple varieties, always finds a home in my garden, kitchen, and freezer. It's all about your preferences (and light/water conditions.)

1. Match requirements - put together plants with the same light and water requirements. You can mix in annuals with the herbs and vice versa. I sometimes through in a hot pepper, Kale, or Asian eggplant for interest. 
2. Seeds or plants - Seeds may give you a wider variety of options than you will get in your garden center. Seeds are also less expensive.  In most of the country, cold climate gardens, seeds will need to be started indoors 1-2 months before they can be moved into containers outside. Plants, ready to go into pots is a convenient option & a great way to start with less effort if you are new to gardening. I usually get most staples as plants - but do a few new options from seed each year. 
3. Numbers of plants per container - I tend to like over crowded containers, however this can slow growth and crowd out some plants while reducing my time weeding.  The container pictured above has just small plants - it will need to be thinned out and items transplanted. But for now, it sure looks cute.
4. Specific herb considerations for some of my favorites:



Chives and oregano in the herb garden

• Chives - These are hardy Zone 3-10 so you can leave them in the container year after year. Clump-forming perennials - they will eventually fill a container by themselves.
• Basil - can tolerate short period of drought. Grows well with thyme and parsley. It can get tall - there are small varieties Boxwood is nice and great for pesto. Purple Ruffles Basil adds color while tasting like licorice. Thai basil another fun add. Consider planing multiple basil plants. It takes 3 cups of fresh basil to make pesto for 1 pound of pasta. Plus, once basil starts to flower it's near impossible to get it to go back to leaf production (plant in stages)
• Lavender - Love it, have trouble getting it to take as Perennial. Not all varieties are hardy in a cold climate. 
• Oregano - The more sun it gets the stronger the flavor. I've used a Greek oregano variety that takes over everywhere it touches. Doesn't like wet soil.
• Mint - vigorous and aggressive.Very forgiving on light, water, and soil condition.  Always grown in pots & never let it seed. I like growing fun varieties like orange mint. 
• Rosemary - loves full sun and average soil. Keep the pot to under three gallons if growing it alone. Need to pull it inside in winter. 
5. What goes with what - there are lots of options. Some fun ways to arrange are:

• Italian Herb Container garden: Basil, oregano, parsley, sage, rosemary, thyme (through in a few garlic bulbs to harvest in the fall)
• Aromatics Container Garden: Sage, Lavender, Chamomile
• Tea Container Garden: Spearmint, Peppermint, Chamomile
• Pizza Container Garden: Parsley, Basil, Oregano, Chives, Garlic (Dwarf Tomato plant)
• Herbes de Provence Container Garden: Thyme, rosemary, marjoram, basil, savory, summer savory
• Asian Cuisine Container Garden: Parsley, Mint, Thai Basil, (Chinese Eggplant, Hot peppers, garlic)
• Mosquito container gardens ; Please see my blog for more details to consider. 

HARVESTING:  Pinch back the herbs as they first start growing to help them develop into bushy and compact plants. While commercially harvesting herbs is most optimal when the flower buds start to appear - do not let your herbs flower, this will reduce the leaf growth and may change the flavor of the herb. In your container garden you may harvest to control growth and for your own culinary needs! The more your pick, the more it grows, the more you get :) Always harvest the older stems first - don't just cut down the whole plant. For perennial herbs, like Sage, Mint and Thyme,  you can remove the top third of the plant/branch when you harvest (in addition to taking pieces as needed.) For annual herbs,  leave several inches of shoots for regrowth. Perhaps 5 inches or so should be left. This is also a good rule of thumb, don't harvest unless they are at least 6-8" tall. Watch how the plant grows - so for example, Parsley and Chives grow from the the center/bottom in this case cut the oldest parts out completely.  Here's a good crafty DIY piece on how to dry herbs and some more details on harvesting herbs on this blog post. 

Have a great time experimenting with your Herb Container Garden. I'd enjoy hearing your tips and news in this regard.  Also you may be interested in my blog on maintenance for herb gardens or how to make compound butter and herb flavored vinegar and oils with your fresh herbs.

Signing with the birds on this spring day!

Teresa Marie