You can succeed growing your herbs in containers if you take a few things into consideration.
Do note the feeding regimes – this is different than growing herbs in the ground.
Use a Big Container
Use the largest containers you can. You’ll find the growth of culinary herbs is much better if given the root space and not squeezed tightly together.
I tend to use a minimum of a 16-inch pot for my container herb gardens.
Soilless Mix from Top To Bottom
Many gardeners use soil from their gardens or regular potting soil (the kind you use for houseplants that contains real soil).
This is a mistake for container gardens.
Use a soilless mix such as Promix. You do NOT want any real soil in the container because it will turn to concrete as the growing season progresses. (The weight of all the water you’re going to put onto the pot all at once every time you water will smush the soil particles together. So if there’s any clay at all, it will compact terribly.)
Check the label – even some of the most popular and heaviest advertised potting soils contain real soil and you do want to avoid this. (What happens if you do use real soil? The soil will compact too soon and your harvests will go down.)
Use the same soil from top to bottom of the pot and don’t put shards or anything on the bottom of the pot to “improve” drainage. Adding larger material actually slows down drainage.
If you’re growing annual herbs such as basil, then adding 10% compost to the soil is a good idea to keep the plant growing strongly.
Otherwise, use fish emulsion at recommended rates every two weeks.
My tender herb container. I overwinter it in the cold cellar
If you’re growing perennial herbs, then a mix of compost is acceptable or a monthly feeding of fish emulsion will keep the herbs growing but not turn them too soft.
Grow as many herbs as you can in the same container. My rosemary container (I overwinter it indoors) contains two varieties. It used to have three but I killed one accidentally. I have an upright variety growing up and a trailing variety growing over the edge.
Feeding and Harvesting
I know you want to know – if you’re growing a combination – I’d feed every two weeks.
I use fish emulsion.
The simple deal is that while herbs growing in garden soil don’t require feeding, there’s an important difference to understand.
In regular garden soil, there are a great many micronutrients plants require but in soilless container soil, there are almost none. You have to provide them if you want to see growth.
In regular garden soil, there are essential nutrients at low levels (nitrogen etc) but again, these don’t exist in soilless mix. You have to provide them.
You’ll simply get a better crop if you feed your container herbs.
Harvest regularly (even if you don’t need the herb) to keep the plant producing new, tender shoots.
Lemon Verbena on my own back stairs – perfect for fast lemony drink flavors. You can see my rosemary in the background, the one with the shorter, evergreen-like leaves
Your Plant Choices
Grow what you’ll use most of. For example, most folks I know will use and really enjoy fresh basil with tomatoes. And the rules for growing basil in the garden (pruning etc) are the same for in the house.
- Start simple.
- Start with annuals because they’re the easiest and don’t require a dormancy period.
- Note that perennial herbs really don’t come into their own until the second year after planting.
- Start with what you use.
- Put the pot in the full sun. Herbs don’t grow well in shady conditions.
- In shade, you’ll get some growth (spindly and weak) but the taste/flavor is watered down by the spindly weak growth.
Container Herb Gardening Locations
- Put the herb container where you’ll be able to harvest it easily and regularly. In the full sun.
- If you have a regular garden, use the container grown herbs for quick pick-me-ups for taste in drinks or salads. A little basil, a little mint, small chives, a touch of oregano – grow what you’d use in quick cooking. Put the main crop of normal herbs and those you only use once in a while out in the ground-garden.
- In a patio gardening herb garden, mix and match your herbs – growing the taller herbs in the center of the pot and the shorter ones to the edges. Plant any trailers or ground cover types on the edges and let them find their own airspace.
- Plan on taking the container indoors in the fall and harvesting it until the plants run out of energy and sunshine (becoming spindly or dying). Full sunlight and cool temperatures (low 60’s to mid-50’s F) will prolong this fading away.
- When annual herbs start to fade, toss them into the compost.
- I don’t try to keep perennial plants growing but when I bring them indoors, they go immediately into the cold cellar for the winter.
Tropical perennial herbs (lemongrass etc) need full sunlight and warm temperatures to continue growing so you either provide these or the plant will fade and die.
Will Perennial Herbs Live Over The Winter If I Dig Them Up From The Garden
As a rule of thumb, they’ll live for a while but stop growing around December and by the end of January, they’ll look really poor.
And then when you put them back outside again, they’ll languish for the summer. You see, perennials want and need to go dormant and when you bring them indoors, they don’t get the rest they need.
What About Parsley? I’ve Read You Can Bring That Indoors
True. It’s a biennial so if you bring it indoors, it will continue growing and then you can toss it out in the spring and start with a new plant.
Feeding The Plants
In the garden, we tend not to feed herbs too much.
But in a container, those rules don’t hold true. For best results, you do want to feed an organic liquid fertilizer on a weekly basis to keep those annual herb leaves coming along.
Pruning and Harvesting
When you harvest leaves from the top of the plant, it stimulates growth from below the cut.
But in the winter, there’s not much light to stimulate new growth. It will take a while to get those side shoots performing but the rule of thumb still holds true. Pinch and prune from the top to get the plant to bush out and then take uniformly from the mature shoots.
How Long Will The Herb Last
Well, that depends on how hard and how often you harvest the leaves. There’s no hard and fast rule here – it you give a plant enough light to keep it growing (hard to do without grow lights in the reduced light of winter) then it will produce as much over the winter as it does in the summer. My ebook on growing herbs is here.
But as the winter light levels go down, production will go down. That’s the Internet’s way of saying it all depends on how much light and heat you can give the plant and there’s no way that one size fits all.
Heat? Yes, don’t forget that the temperature on a windowsill in the winter is going to be colder than the room temperature and that annual herbs want all the heat and light you can give them.
Doug’s Bottom Line
It really isn’t rocket science and herbs are really no different than other plants.
The most important advice I can give you is to simply do it. Enjoy the experience and do brush your hand against the herbs now and then to get those delicious gardening fragrances.
Read other herb gardening articles here