Setup to harvest without soil

Hydroponics

In hydro the roots sit in oxygen-rich nutrient water instead of soil, so plants grow faster — and problems also move faster. Success comes down to four numbers you check daily: pH, EC, water temperature and dissolved oxygen. Deep Water Culture (DWC) is the easiest place to start.

1. 1Choose a system

   • DWC (Deep Water Culture): one 5-gallon (19 L) bucket per plant, net pot on top, air stone below. Cheapest and simplest. Roughly $40–100 per bucket.
   • RDWC (Recirculating DWC): several buckets linked to a control reservoir. More stable pH/EC across plants; best for 4+ plants. Roughly $300–800.
   • Ebb & flow (flood and drain): a tray floods from a reservoir on a timer, then drains. Forgiving if the pump fails briefly.
   • NFT and aeroponics: very efficient but least forgiving — a pump failure can kill roots within hours. Not recommended for a first grow.
   • Medium: clay pebbles (hydroton) in net pots, with the seedling in a rockwool cube or starter plug.

2. 2Set up the system

   • Use opaque, light-proof reservoirs and lids. Any light reaching the water grows algae.
   • Air pump: size about 1 L/min of air per litre of water (or larger). Place the pump above the water line or use a check valve so water can't siphon back.
   • Keep water at 18–21°C (65–70°F). Above 22°C oxygen drops and root rot (Pythium) becomes likely; use a water chiller in warm rooms.
   • Fill with RO or low-mineral tap water. Let chlorinated water sit 24 h or use a dechlorinator; chloramine needs a neutraliser.
   • Calibrate pH and EC meters before every reservoir change. Run the empty system 24 h to check for leaks and pump noise.
   • Optional but recommended: beneficial bacteria (e.g. Hydroguard or similar Bacillus products) to protect roots.

3. 3Germination & seedlings

   • Soak rockwool cubes in water pH'd to 5.5 for an hour, then squeeze out lightly. Starter plugs need no soak.
   • Germinate seeds in a paper towel, then place the taproot down in the cube. Keep cubes warm (24–26°C) and humid (70–80%).
   • Once roots poke out of the cube (7–10 days), place it in the net pot surrounded by rinsed clay pebbles.
   • Set the water 2–3 cm below the net pot base so the cube is kept moist by bubbles. Hand-water the top of the cube for the first few days.
   • Seedling solution: EC 0.4–0.8 (200–400 ppm), pH 5.6–5.8. As roots grow into the water, lower the level to leave an air gap.

4. 4Vegetative growth

   • Hydro plants veg very fast. Top, LST or SCROG early because they will fill the tent quickly.
   • Solution EC 1.0–1.6 (500–800 ppm), pH 5.6–6.0. Light 18/6 at 400–650 PPFD.
   • Healthy roots are white or cream, firm and smell earthy. Brown, slimy, smelly roots = root rot.
   • Top off with plain pH'd water as the plant drinks. If EC rises, plants are drinking more water than food — top off with plain water. If EC falls, they are eating more — top off with a weak nutrient mix.

5. 5Weekly feeding schedule (3-part salts, photoperiod)

   • Week 1 seedling: EC 0.4–0.6 · pH 5.8 · Cal-Mag 0.5 ml/L if using RO.
   • Week 2 seedling: EC 0.6–0.8 · pH 5.8.
   • Weeks 3–4 veg: EC 1.0–1.2 · pH 5.7–5.9 · grow-heavy ratio.
   • Weeks 5–6 late veg: EC 1.2–1.6 · pH 5.8–6.0.
   • Flower weeks 1–2 (stretch): EC 1.4–1.6 · switch to bloom ratio · pH 5.8–6.0.
   • Flower weeks 3–5: EC 1.6–2.0 · pH 5.9–6.2 · add PK booster at half dose if desired.
   • Flower weeks 6–7: EC 1.6–1.8 · begin tapering.
   • Final 7–10 days: plain pH'd water or EC under 0.4.
   • Autos in hydro: run about 70–80% of these EC values and expect harvest around week 10–11 from sprout.
   • Always start at half the bottle dose and watch the leaf tips: burnt tips = lower EC, pale lower leaves = raise EC slightly.

6. 6Reservoir maintenance

   • Check pH and EC daily. Let pH drift naturally between 5.6 and 6.2 — different nutrients absorb best at different points.
   • Change the whole reservoir every 7–10 days. Rinse the bucket, inspect roots, and refill fresh.
   • Keep a log of each change: date, volume, EC, pH, water temp, additives. Use the Journal in this app.
   • Clean air stones between grows (or replace). A dead air pump is an emergency in DWC — keep a spare.

7. 7Common hydro problems

   • Root rot: brown slimy roots, wilting despite water. Cool the reservoir below 21°C, increase air, add beneficial bacteria, change the solution. Hydrogen peroxide can rescue but also kills beneficial microbes — don't combine them.
   • pH swinging fast: often root rot or too-small reservoir. Larger water volumes are more stable.
   • Algae: green film on pebbles or reservoir. Light leak — cover everything.
   • Calcium/magnesium spots: very common with RO water. Add Cal-Mag first.

8. 8Flowering & harvest

   • Flip photoperiods to 12/12 once plants fill about half the space — they can double or triple in stretch.
   • Lower humidity to 40–50% in late flower; hydro buds swell fast and dense buds rot easily.
   • Harvest by trichomes: mostly cloudy with 10–30% amber. Then dry and cure exactly as in the Dry & Cure lesson.