I almost never buy fresh herbs at the store unless I have a specific need—but when they’re right outside my door in the garden in the warmer months, I use them in everything. When things cool off, though, you can keep fresh herbs close at hand by growing them inside—but that’s not without its challenges. The little potted versions you see at grocery stores like Trader Joe’s are tempting, but people quickly realize that keeping those potted plants alive is tough. Here are some tips to help you prolong the life of potted herbs so you can enjoy them all winter long.
How to pick the herbs you’ll grow inside
Some herbs, the hardier stock, do fine outside all winter. Winter thyme and rosemary overwinter fine, you can pull oregano out, even dry, all winter; even some kinds of parsley can remain lively into the coldest months. Focus inside on more tender herbs like dill, cilantro, and basil. When choosing plants, look for those with large, fluffy leaves, rather than the biggest plants. You want to avoid any that are going to seed, so avoid those with flowers, and even those with wispy leaves at the top, which is a sign they’re about to go to seed. You’re looking for strong stems more than anything else, but avoid diseased leaves or any plants where the stems are a tangled mess.
Thin the seedlings and repot them
The farms that grow these little pots overseed them, so where one basil plant should grow, there are twenty or more. They do this so the pots look fuller, but all those seedlings competing for resources means the plants can’t thrive. So step one is to separate the seedlings and break them out into other pots. You can buy four-inch pots online relatively cheaply, or use pots you already have. You’ll want to take the entire plant out of the pot, and then carefully separate the roots as if you are breaking apart knots in your hair, carefully raking the roots free.
In each four-inch pot, you should really only have one or two seedlings. Although it might feel painful, don’t feel too bad about composting a lot of extra seedlings. Use the herbs, and then just compost the extra stems. Be sure you’re repotting into potting soil, not raised bed soil. Now, water in your new seedlings, by giving them a sip of water. Do not drown them, though—you want moist soil, not wet soil.
Transplanting is really stressful for plants, so you need to let them have a day out of bright sunlight so they can adjust. They should be in moderate temperatures (60-80 degrees) as close to the environment you bought them in as possible. Once they’ve had a day to recover, you can move them to a spot with direct light near a window.
Feed and water your plants regularly
Knowing when to water is really key. As your plants adjust to their new pot and home, they may experience stress and drop their leaves. Don’t give up hope. That’s a natural reaction; it doesn’t mean the plant is a goner. Don’t overreact and water them to death. Just give them a day or two to recover. When the plant is dry, it’s time to water. Water until it comes out of the bottom of the pot, and then allow the plant to drain and dry. Conversely, I like using saucers of water under the pots, I just leave a little water in them, sit the pot in the water, and allow the plant to uptake whatever water it needs.
Every other week, I give the plant a light amount of fertilizer, like Miracle Grow, in the water. You can find plant food at any garden center; just follow the directions on the bottle.
To keep herbs alive, use them
A mistake people often make with herbs is not being severe enough when harvesting. If you want herbs to stick around, you must chop them back frequently. Not a light clip, but a real chop. This will tell the plant to focus on leafy growth instead of flowering and seeding. Your stems will grow back bushier and stronger, and as long as you keep at it, you should be able to prolong your plant life pretty reasonably. Now, some herbs are more prone to bolting, like cilantro and dill, so they’re not going to live forever, but they’re not meant to. They’re annuals, not perennials. So once that happens, just start over with a new grocery store plant.