Growing thyme with Kratky hydroponics
Kratky Thyme
Thyme can grow in a Kratky container, but it is slower and fussier than basil or mint. Here is how to give it the best chance, and what to expect.
The honest answer
Does Thyme Work with the Kratky Method?
Yes, with patience. Thyme (Thymus vulgaris) is a small, woody Mediterranean shrub that grows wild on dry, rocky ground. It wants sharp light and dislikes wet roots near its stem, the opposite of a leafy herb like basil. In a Kratky container it grows more slowly than leafy herbs, and it fails mostly when its crown sits too wet.
The Kratky method suits thyme better than many hydroponic systems, though, because the falling solution level leaves more and more of the root zone in air. Set it up so the base of the stem stays dry, and thyme gives a steady supply of small, fragrant sprigs.
slowbut steady
Getting started
Cuttings or Seed?
From a cutting (best)
Take a 3 to 4 inch soft, green tip from a nursery plant, strip the lower leaves, and root it in water or a moist rockwool cube. Rooting takes two to four weeks, longer than mint.
From seed (slow)
Thyme seed is tiny and slow. Press it onto a moist cube without covering it; it sprouts in one to three weeks and takes a couple of months to reach a usable size.
Step by step
How to Set Up Kratky Thyme
Choose a dark container
A pint or quart jar, wrapped to block light, is enough for one plant.
Use a gritty medium
Clay pebbles in the net pot drain well and keep the stem base drier than rockwool alone.
Set the level low
Fill so only the very bottom of the net pot touches the solution, and the stem stays well above it.
Give strong light
As much direct sun as you have, or 12 to 16 hours under a grow light. Weak light gives thin, leggy thyme.
Let it run down
Let the level fall well away from the net pot. Top up part way only if it is nearly empty.
Harvesting
Cutting Thyme Without Hurting It
Wait until the plant is bushy and about 6 inches tall. Then snip green sprig tips, taking no more than a third of the plant at a time. Never cut back into the bare, woody stems; thyme regrows from green growth, not from old wood.
Thyme's flavor is strongest just before it flowers. It dries very well, so a big harvest isn't wasted; see preserving your herb harvest.
1/3at most per cut
Problems
Common Kratky Thyme Problems
Most thyme problems come back to the same two things: too much water around the stem, and too little light. Fix those first before anything else.
- Brown, dry-looking stems at the base: the crown has stayed wet and is rotting. Lower the solution level, use clay pebbles, and take a cutting from the healthy top as a backup.
- Long, thin, floppy stems: not enough light. Move it to the sunniest window or closer under the grow light.
- Grey, dusty coating on the leaves: powdery mildew, common indoors in still air. Improve air movement, thin crowded stems, and cut affected sprigs out.
- Very slow growth: normal for thyme in its first weeks. If it lasts more than a couple of months, check light first, then the solution.
- Leaves turning yellow from the bottom: old leaves ageing, or the solution is spent. Cut them out and top up part way with fresh solution.
FAQ
Kratky Thyme Questions
Why is my Kratky thyme dying at the base?
The crown is too wet. Lower the solution level or raise the plant in the net pot so the stem base stays dry, and use clay pebbles.
How long does thyme take to grow hydroponically?
Expect two to three months from a rooted cutting to regular harvests, longer from seed.
Which thyme is best for Kratky?
Common or English thyme is the most reliable. Lemon thyme also grows well.
Can thyme share a container with other herbs?
Only with herbs that like the same drier, brighter conditions, like oregano. See mixing herbs in one container.
Does thyme need special nutrients?
No. A standard herb nutrient works. Some growers use it a little weaker for woody herbs.
Can thyme grow from a grocery store sprig?
Fresh, soft green sprigs sometimes root in water. Older, woody sprigs rarely do, so a nursery plant is a more reliable source.
How do I keep Kratky thyme from getting woody?
Cut green tips regularly from the start. Frequent light harvests keep the plant bushy and slow the spread of bare, woody stems.
Related Kratky Herbs
Thyme's closest partner in the kitchen and the jar is oregano. Rosemary is the slowest of the woody herbs.