To keep a cannabis mother plant, hold it in vegetative growth with 18 to 24 hours of light per day, keep temperatures near 70 to 80°F, feed a mild nitrogen-forward formula, prune and root-prune on a schedule, and replace the plant every 3 to 6 months before vigor drops. A mother plant is a stock plant kept from flowering so you can take cuttings. Treat it as a long-term crop, not a flowering plant.
What light schedule keeps a mother plant in veg?
Use 18 hours on and 6 hours off, or 24 hours on if your room stays cool. A mother plant can flower if it gets 12 hours of darkness, so seal light leaks and use a timer. Keep PPFD around 300 to 600 µmol/m²/s for stock plants. Stronger light can push dense growth that is harder to manage.
Best Soil for Cannabis Mother Plants: 5 Options Compared
What temperature and humidity does a mother plant need?
Target 70 to 80°F at canopy level and 40% to 60% relative humidity. Stable conditions limit stretch, powdery mildew, and mite outbreaks. Run gentle airflow across the canopy but do not blast the root zone.
how to keep a cannabis mother plant
What pot size and growing medium should you use?
Use a 3 to 5 gallon pot with a drain hole for a plant you will keep for months. Coco coir, peat-based mix, or a mild organic soil all work when drainage is good. Fabric pots air-prune roots, but they dry faster than plastic.
Root prune every 3 to 6 months if the plant stays in the same pot. Slide the root ball out, slice off up to 1 inch from the sides and bottom, and repot into fresh medium. Do this in veg and give the plant 1 to 2 weeks to recover before you take cuttings.
How should you feed and water a mother plant?
Feed a vegetative formula with nitrogen, phosphorus, and potassium plus calcium and magnesium. Keep EC near 1.2 to 1.6 in coco or hydroponics, or follow the soil label at half strength. Water when the top inch of medium dries, and water until 10% to 20% runoff.
- Use mild nitrogen to support leafy growth without soft, weak stems.
- Add calcium and magnesium if you use coco or reverse osmosis water.
- Flush with plain water every 4 to 6 weeks to clear salt buildup.
How do you prune and train a mother plant?
Top the main stem above the fifth or sixth node to create side branches. Remove lower growth that gets little light, and keep 8 to 12 strong tops for cuttings. Pinch or tie branches to keep the canopy even and open.
Clean pruners with alcohol before each plant. Remove dead leaves and inspect the undersides of leaves for mites and thrips. A mother plant stays in veg, so you can prune it any time without a flowering deadline.
How do you take cuttings from a mother plant?
Take cuttings from healthy lower or middle branches that have at least three nodes. Cut at a 45 degree angle just below a node, dip the stem in rooting hormone, and place it in a moist cube or plug. Keep the cutting under a dome at 70 to 75°F and 60% to 70% humidity until roots show in 7 to 14 days.
When should you replace a mother plant?
Replace the mother every 3 to 6 months, or sooner if growth slows, leaves yellow, pests return, or cuttings root poorly. A fresh cutting from a proven plant preserves the genetics better than an old, woody stock plant. Keep two mother plants from the same genetics so you always have a backup.
How do you prevent pests and disease on mother plants?
Quarantine new plants for 2 weeks before they enter the veg room. Use sticky traps, inspect leaf undersides weekly, and keep the room clean. Treat mites or mildew early with an integrated pest management plan, and never take cuttings from an infested plant.
Can you keep a mother plant forever?
No. A mother plant can live for years in veg, but vigor and cutting quality decline. Most growers refresh the stock plant every 3 to 6 months, or at least every year.
Do mother plants need a dark period?
Not strictly. Many growers run 24 hours of light to slow stretch and keep growth steady. An 18/6 schedule uses less power and gives the plant a rest period.
Can you flower a mother plant later?
Yes. A mother plant can be moved to a 12/12 light schedule and flowered. Prune it back and repot it first, because a large root-bound plant can stretch hard in flower.