Growing questions
The questions growers ask most, with an honest answer and the gear that goes with it. Can’t find yours? Ask below.
- Problems & pests Why has my plant stopped growing in flower? Some slowdown after the first weeks of flowering is normal. If it stalls hard, check pH and EC, roots, temperature and light. Read the answer →
- Problems & pests Why are my leaves curling? Edges curling up like a taco usually mean heat or too much light. Tips curling down in a claw shape often mean overfeeding, or sometimes overwatering. Read the answer →
- Problems & pests Why are my plant's leaves turning yellow? Usually it is a nitrogen shortage, overwatering, or a pH problem. Where the yellowing starts tells you a lot. Read the answer →
- Problems & pests How do I get rid of fungus gnats? Let the top layer of the medium dry out between waterings, hang sticky traps, and use biological control against the larvae. Read the answer →
- Problems & pests How do I get rid of spider mites? Isolate the affected plants, wash the leaves, and treat early with an approved product or predatory mites. Mites double in numbers fast, so do not ... Read the answer →
- Problems & pests How do I get rid of powdery mildew on my plants? Pull off the affected leaves, drop the humidity, get more air moving, and never spray anything on flowers. Catch it early, because it spreads fast. Read the answer →
- Water, pH & EC What is the ideal water temperature for my plants? Roughly 18 to 22 °C. Colder water slows the roots, warmer water above about 24 °C makes root rot much more likely. Read the answer →
- Water, pH & EC Can I use tap water, or do I need reverse osmosis water? Tap water is fine if it's moderately hard (EC below roughly 0.8). RO water is a blank slate for exact control, but you must add Cal-Mag. Read the answer →
- Water, pH & EC How do I raise or lower the pH of my water? Use pH-down to lower it and pH-up to raise it. Add drop by drop, stir, wait a minute and re-measure. Read the answer →
- Water, pH & EC Why does my pH keep dropping in my DWC reservoir? A steadily dropping pH usually means the plants are taking up ammonium and cations, or the root zone is too warm or infected. Check water temperatu... Read the answer →
- Water, pH & EC How often should I calibrate my pH meter? Calibrate before any measurement that matters, roughly every couple of weeks with regular use, and always when readings look odd. Read the answer →
- Water, pH & EC Which pH and EC meter should I buy? Buy a meter with a replaceable probe, temperature compensation and calibration solutions you can get easily. A pen meter is fine for a small grow. Read the answer →
- Water, pH & EC What EC should I use at each stage? Typical EC runs about 0.4–0.8 for seedlings, 1.0–1.6 in growth and 1.4–2.0 in flower (mS/cm). Variety, medium and brand move it up or down. Read the answer →
- Water, pH & EC What pH should my nutrient solution be? Roughly 5.8–6.3 for coco and hydro, and 6.0–6.8 for soil. Read the answer →
- Nutrients Can I mix nutrients from different brands? You can, but I'd stick to one brand at first. Charts only add up if you use the products they were designed around. Read the answer →
- Nutrients When should I stop feeding before harvest? Most charts end with 1–2 weeks of plain water before harvest, but the exact timing depends on the brand and medium. Follow your chart. Read the answer →
- Nutrients How can I tell nutrient deficiency from overfeeding? Look at where the problem starts. Pale or yellow older leaves point to hunger, dark glossy leaves with clawing and burnt tips point to too much feed. Read the answer →
- Nutrients Organic or mineral nutrients, what's the difference? Organic feeds work through soil life that breaks things down, so they are slower and more forgiving. Mineral nutrients are ready for the roots righ... Read the answer →
- Nutrients What do root stimulators do, and when do I use them? Root stimulators help new roots form, so use them on cuttings, seedlings and transplants. They're nice to have, not a must. Read the answer →
- Nutrients Do bloom boosters actually work? PK boosters can help a little in the middle of flower, but they won't rescue weak light or sloppy feeding. Be wary of products that are really grow... Read the answer →
- Nutrients What does silicon do for plants? Silicon builds stronger cell walls, which helps stems and the plant's stress tolerance against heat, drought and some pests. It's a nice extra, not... Read the answer →
- Nutrients What is Cal-Mag, and when do I need it? Cal-Mag is a calcium and magnesium supplement. You mostly need it in coco and with soft or RO water, or when new leaves show spots or twisting. Read the answer →
- Water, pH & EC How often should I change the water in my reservoir? In recirculating hydro, every 1 to 2 weeks. In soil or coco you mix fresh feed for each watering, so there is nothing to change. Read the answer →
- Water, pH & EC Does hard tap water cause problems for my plants? Yes, it can. Hard water brings calcium, magnesium and bicarbonate along, which pushes pH up and adds EC before you have added any feed. Read the answer →
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