Days to germination: 7 to 10 days
Days to harvest: One summer season
Light requirements: Full sun
Water requirements: Only when very dry
Soil: Light and well-drained
Container: Suitable, and preferred for colder areas
Thyme is a perennial plant that thrives in warm dry conditions, reflecting its Mediterranean origins. It’s a low-growing plant that can even be used as an ornamental ground cover. Thyme seldom grows higher than 12 inches, with some varieties only reach 2 or 3 inches in height.
Depending on how often your harvest, most thyme plants will keep giving you a harvest of leaves for 5 years before getting too woody.
You won’t be able to grow thyme outdoors if you have cold winters though because it’s not that hardy when it comes to cold. Zones 5 through 10 are the ideal locations for growing this herb but you may be able to keep your plants indoors instead.
Thyme leaves are quite high in vitamin K as well as iron. It’s a savory herb used with meats, but can also be brewed in a tea. Thyme tea is reputed to help with headaches, cough and sore throats.
Starting from Seed
Most people start their thyme from seedlings, or plant divisions from someone they know who grows thyme. It can be started right from seed if you prefer.
You can start your seeds indoors and transplant the seedlings into the garden to give them a better start. Sow your seeds about 4 to 5 weeks before your last frost date, only covering the seeds with a light sprinkling of soil.
The flowers of the thyme plant are great for attracting bees, so you may want to plant it near to your vegetable garden if you have other plants needing help with pollenization. The aromatic leaves are known to repel several kinds of cabbage flies as well.
The best spot for growing thyme is very sunny, with light or even slightly sandy soil. Thyme might be a good option for patches of poor soil where little else will grow.
You will want to put your seedlings out after your frost date. They can be a little delicate, so it’s best if you do it gradually by hardening them off first. For 4 or 5 days, put the seedlings outdoors for the day but bring them back inside during the night. They will suffer less shock at planting time if you do this.
Your seedlings should be 6 to 12 inches apart, depending on the variety. The more upright growing plants will take less space than the creeping thymes.
If you do plant out seeds right into the garden, you can either broadcast the seed and thin later, or keep your seeds to a 6-inch spacing.
Thyme is a very hardy little plant, and too much care can do more harm than good. Plants will prefer to be slightly dry rather than over-watered so you only need to give them a drink in very hot weather.
Once a year fertilizing in the spring will keep your plants at their best, unless you have planted your thyme in particularly poor soil. In that case, a feeding in the spring and fall wouldn’t hurt. But neither option is a necessity. Thyme can grow quite well without additional nutrients.
As the plant gets older, it will get very woody. You’ll want to prune back some of the larger branches to encourage fresh growth with new leaves.
A creeping type of thyme can spread quite a bit, and may escape its proper garden area. The stems can root down and spread quickly, so either keep your plants well trimmed or surround your thyme with a bit of garden edging to keep it contained.
Most varieties of thyme will grow well in containers. Very low-growing ones such as lemon thyme or caraway thyme will very quickly spill over the sides of their pots, because they grow out rather than up. Give them extra space to trail out of their containers. They will need a full days sun as well.
Each plant will need a pot approximately 10 inches across, filled with loose potting mix. Just like in the garden, thyme does not like too much water. Let the soil dry out between waterings.
Pests and Diseases
Not only is it hardy, but thyme is relatively pest-free as well.
They can attract tiny little spider mites, which are seldom a serious threat to the plant. But nobody wants to bring bugs inside when harvesting leaves, so you can give your plants a squirt or two with the hose to wash them off. If it is a persistent problem, a regular treatment with a natural insecticide can help.
One of the biggest problems is due to over-watering. Thyme is sensitive to excess water around the roots and can easily develop root rot. Do not over-water your plants, they really do better when its dry. Also only plant in areas with very loose soil.
Harvesting and Storage
Let your plant grow for most of the first year without any harvesting to let it mature and develop some strong roots. You can start picking leaves towards the end of the first summer if you want. After that, pick as often as you need thyme, providing you don’t strip more than a third of the leaves off at any one time.
You can use fresh thyme, both as a seasoning or as a green in salads. Fresh leaves will keep for about a week in the fridge. The most common way of storing thyme beyond that is by drying.
Just snip off some branches, and hang in a ventilated place but out of the sun. When they are dry right through, take the leaves off the branches and store in an air-tight container. The branches are too woody to be used for anything, just store the leaves themselves.
Thyme does fine frozen but dried thyme will keep its flavor better than frozen.