Kratky Harvest: When and How to Harvest a Kratky Kit

Harvest is the step most Kratky guides skip, yet the way you harvest decides how much you get from one fill of solution. A Kratky kit runs on a single batch of nutrient, so timing the harvest to the plant and to the falling water level is part of the method.

Two ways to harvest

Whole-plant vs cut-and-come-again harvesting in a Kratky kit

	Whole-plant harvest	Cut-and-come-again
How	Lift the net pot and cut the plant at the base, or remove it with roots	Pick outer leaves or cut stems, leaving the growing center
Suits	Head lettuce, bok choy, a crop you want finished in one go	Loose-leaf lettuce, kale, chard, most herbs
Solution	Container is emptied and cleaned after	Plant keeps drinking; the reservoir must last longer
Best when	The plant reaches full size, before it bolts	The plant is big enough to lose a third of its leaves

How to tell a crop is ready

• Loose-leaf lettuce: outer leaves are a usable size, usually a few weeks after transplant. You can start picking long before the plant is full size.
• Head lettuce: the head feels firm and full. Harvest before the center starts to stretch upward.
• Basil: the plant has several pairs of true leaves and is bushy enough to lose its tops.
• Mint, oregano and thyme: stems are long enough to cut while leaving a few sets of leaves.
• Parsley and cilantro: outer stems are full size. Cilantro bolts quickly in warmth, so pick early and often.

Seed packets give a days-to-maturity figure. It is a useful starting point, but in a kit, light and temperature change the timing a lot, so judge by the plant.

How to harvest lettuce and greens

1. Use clean scissors or a sharp knife.
2. For cut-and-come-again, take the largest outer leaves at the base, leaving the inner ones to grow.
3. Never take more than about a third of the plant at once.
4. For a whole-plant harvest, cut just above the net pot, or lift the whole pot and roots out.
5. Rinse leaves in cool water and refrigerate soon after cutting.

The Kratky lettuce kit walkthrough follows one crop from seed to harvest.

How to harvest herbs

Most herbs grow back bushier when cut just above a leaf node, the point on the stem where a pair of leaves grows. New shoots form there. Pinching out the tips of basil this way, and removing flower buds as they appear, keeps it producing leaves for longer. Woody herbs such as thyme and rosemary should not be cut into old, bare wood. The article on the Kratky herb kit covers herbs in more detail.

Harvest timing and the water level

In a Kratky kit the water level falls as the plant drinks, and a large plant drinks fastest. That makes the reservoir a useful harvest signal:

• If the plant is ready and the reservoir is low, harvest. There is no reason to top up a finished crop.
• If the plant is not ready and the reservoir is nearly empty, add a little fresh solution below the air roots, as the guide on how often to refill a Kratky kit explains.
• Cut-and-come-again plants keep drinking, so a long harvest needs a bigger container from the start. The Kratky containers guide gives sizes.

Signs you waited too long

• Bolting: lettuce or cilantro stretches upward and starts a flower stalk. Leaves turn bitter. Harvest at the first sign.
• Flowering basil: leaves become smaller and stronger tasting. Pinch flowers off, or harvest the plant.
• Tough, woody stems on herbs left uncut.
• Yellowing outer leaves as the solution runs out.

Heat and long days both speed up bolting, so summer crops often need harvesting earlier than winter ones.

After the harvest

Once a crop is finished, empty the old solution, remove the roots, and clean the container, lid and net pots before the next crop. The article on how to reuse a Kratky kit goes through each step. A fresh start each time is the best protection against root rot in the next crop.

Frequently asked questions