While the garden lies dormant in winter, your hydroponic harvest can simply carry on. That is exactly one of the biggest advantages of soilless growing: it is independent of weather and season. For it to work reliably indoors, though, there are a few winter particulars to keep in mind.
Above all, light and temperature decide between success and frustration in winter. Get both under control and you’ll harvest fresh herbs and salads even in January.
Why hydroponics shines in winter
With no ground frost, slugs or cold, wet weather, your crop grows on undisturbed indoors. You set the light, temperature and nutrients yourself – and so in winter you often have better conditions than outdoors. Lettuce, herbs and microgreens can be harvested fresh all year round this way.
Lighting is everything in winter
The short, weak daylight of winter isn’t enough for vigorous growth – not even on a windowsill. An LED grow light is therefore a must. Plan for 12 to 16 hours of light a day and ideally switch the lamp via a timer so that the rhythm stays constant. Too little light leads to long, pale and weak plants.
Temperature: keep an eye on the room and the nutrient solution
Most crops like room temperatures of around 18 to 22 °C. More critical is the temperature of the nutrient solution: if it gets too cold (say on a draughty windowsill or in an unheated room), the roots barely take up nutrients any more and growth stalls. Keep the solution in the range of roughly 18 to 22 °C where you can, and don’t stand the container directly on cold floors or windowsills.
Dry heated air and humidity
In winter, the dry air from heating gives many plants a hard time. Air the room regularly for fresh air and watch whether your plants are suffering from the low humidity. At the same time, good air circulation is important to avoid mould and stagnant, damp air around the plants.
Suitable plants for winter
Particularly robust and fast in winter are lettuces, kale, chard, herbs and microgreens. They cope well with the shorter days (supplemented by artificial light) and deliver a yield quickly. Heat-loving fruiting plants such as tomatoes or peppers are more demanding in winter, because they need considerably more light and warmth.
The right location
Put your system somewhere free of draughts and away from cold exterior walls or uninsulated windows. A heated cellar or storage room works wonderfully too, provided you supply enough artificial light – the temperature there is often more constant than by a window.
Which systems are easiest in winter
For winter, uncomplicated, low-maintenance systems are especially suitable: the passive Kratky method and compact DWC or herb-tower systems need little technology and run stably. Large, tech-heavy setups tend to be more demanding in winter, because temperature and light problems make themselves felt more strongly there.
Keeping an eye on power consumption in winter
In winter the lighting runs longer, which raises power consumption. An efficient LED and a well-set timer keep the costs within reason. Check whether 12 hours is enough for your plants before you go up to 16 – often less is plenty, as long as the lamp is strong enough and close enough to the plants.
A simple winter harvest calendar
Sow in staggered batches so that you harvest continuously: start a new portion of lettuce or herbs every one to two weeks. That way you always have a fresh supply instead of harvesting everything at once. Microgreens deliver especially quickly and are ideal for having fresh greens regularly through the winter.
Keep an eye on pests in winter too
Indoors, pests such as fungus gnats or aphids can settle in when the heated air is dry. Check the plants regularly, keep the system clean and provide some air movement. Yellow sticky traps help to spot and curb fungus gnats early.
Choosing a location: cellar, storage room or living room
Because you bring the light with you anyway, you are flexible about location. A heated cellar or storage room often offers more constant temperatures than a draughty windowsill. In the living room the system scores as a green eye-catcher – just watch the brightness of the lamp in the evening hours there.
Frequently asked questions about hydroponics in winter
Can I harvest all year round?
Yes. With enough artificial light and a stable temperature, hydroponics runs all year round – that is one of its biggest advantages over growing outdoors.
Is windowsill light enough in winter?
Usually not. Winter light is too weak and too short. An LED grow light running for 12–16 hours is almost always necessary.
Do I have to heat the nutrient solution?
Only if it gets too cold. Below around 18 °C the roots take up nutrients less well. A warm location is often enough; in a pinch, an aquarium heater helps.
Which system is suitable for winter?
Simple, low-maintenance systems such as Kratky or a small DWC setup are ideal. More important than the system are enough light and a stable temperature.
How much electricity does hydroponics cost in winter?
The main factor is the lighting. With an efficient LED and a suitable light duration the costs stay manageable; exact figures depend on the lamp and its runtime.
What is best to grow in winter?
Lettuces, kale, chard, herbs and above all microgreens – they grow quickly and cope well with artificial light.
Can I run hydroponics in the cellar?
Yes, and very well at that – provided you supply enough artificial light. The temperature in a cellar is often more constant than by a window.