Grow tent heater keeping indoor plants warm during winter – Holland Horticulture

How to Warm Your Grow Tent or Room in Winter

By Holland Horticulture • Published Nov 12, 2025

Winter chill can quickly sap vigour from indoor crops. This actionable guide shows how to keep your grow tent or grow room at optimal temperatures using insulation strategies, correct heater selection, humidity control and root-zone care — plus direct links to products on Hydroponics.co.uk to get you set up fast.

Why temperature matters in winter

Most hydroponic crops slow metabolic activity when temperatures drop below ~15 °C; growth and yields suffer. Aim to maintain stable day/night temperatures rather than allowing large swings — stability always outperforms extremes.

Target temperatures

Lights on (day): 20-24 °C (68-75 °F)
Lights off (night): 16-18 °C (60-65 °F)
Rule: avoid night dips below ~15 °C to prevent stalled growth.

Insulation & setup prep

Before you buy a heater, reduce heat loss:

Seal drafts around doors and windows.
Place tents off cold concrete floors (use insulation board or a raised platform).
Use reflective surfaces to reduce heat escape from the canopy area.
Control intake ventilation rates to minimise cold-air ingress during the coldest hours.

Choose the right heater (with direct product links)

Pick the heater type that matches your space and avoid overheating plants or drying air excessively. Below are recommended options from our collection:

LightHouse Ecoheat Tube Heater — space-efficient tube heater that gently raises ambient temperature; ideal for tents and smaller rooms.
Grow Warm Oil Radiator — oil-filled radiator providing even, convected warmth without cold drafts.
2 KW Fan Heater — useful for larger grow rooms; pairs well with thermostatic control to avoid over-run.
Day/Night Temperature Controller — a smart add-on to manage lighting cycles and heating with precision.
Heated Electric Propagators — useful when growing seedlings or young plants in colder environments.

Pro tip: Pair any heater with a dedicated thermostat or temperature controller so the heater only runs when necessary — this saves energy and reduces stress on plants.

Ventilation, humidity & root-zone warmth

Heating the air is only part of the solution. Keep humidity and root temperatures controlled:

Humidity: Cold air holds less moisture — target ~40-60% RH depending on growth stage; use a humidifier if needed.
Root zone: Insulate pots or use a root-zone heating mat (search root heater) to prevent cold roots and sluggish nutrient uptake.
Air circulation: Use gentle circulation fans to even-out heat without blowing cold air directly onto the canopy.

Monitoring & simple winter checklist

Check your environment frequently and be ready to tweak settings early in the season:

Install a digital thermometer/hygrometer at canopy level.
Log daytime and night-time temperatures for the first week after changes.
Look for cold stress: slowed internodes, pale leaves or reduced uptake.
Prepare a fallback plan (temporary booster heater or reduced light schedule) for sudden cold snaps.

Why choose Holland Horticulture’s heating range

Our collection is curated for indoor growers — tube heaters, oil heaters, fan heaters, thermostats and root-heating solutions built to work with hydroponics. Browse the full range here: Grow Room Heaters for Winter - Heating Solutions.

Summary & action items

Place your grow space somewhere thermally stable (avoid exterior walls or unheated garages).
Aim for 20-24 °C (lights on) and 16-18 °C (lights off).
Insulate, seal drafts and raise tents from cold floors.
Choose an appropriately sized heater and pair with a thermostat.
Monitor humidity and root-zone temperatures as well as air temps.
Shop our heater-range: Heating Solutions.

Frequently asked questions

How big of a heater do I need for my grow tent?: Heater sizing depends on tent volume and insulation. For small tents (1-2 m³) an oil radiator or small tube heater often suffices. For larger rooms choose 1-2 kW heaters and always pair with a thermostat.
Can I put a fan heater inside the tent?: It’s safer to place fan heaters outside the tent or mounted so they don’t blow directly onto plants. Fan heaters can dry the canopy so monitor humidity.
Will heating dry out my grow room?: Yes — heating often reduces relative humidity. Use a hygrometer and add a humidifier or adjust your environmental controls to maintain target RH of ~40-60%.
What if my roots get too cold?: Insulate pots, use raised platforms or install a root-zone heating mat to keep root temperatures steady. Cold roots reduce nutrient uptake and slow growth.

Shop Winter Heating Solutions