Frequency more than volume. A light dry back, never a long one.
How often do I water and feed plants in coco?
GROWER ANSWER
More often than soil, in smaller amounts, with feed in the water every time. Coco wants a light dry back between waterings, never the long one a pot of soil wants. There's no fixed number of waterings. Lift the pot, and let the weight tell you when it's time again.
Frequency more than volume.
Why coco isn't soil
Our watering page is written for soil, where you wait until the pot is noticeably lighter. Coco runs on a different rhythm.
It carries little or no food. Most bagged coco has no nutrients mixed in, so you feed it from the very first watering. A few blends have some added, so read the bag.
It holds much less in reserve. Soil buffers what you give it. Coco holds far less, so what you feed reaches the roots more directly, good and bad.
It dries back faster. The usual bagged coco and perlite blends dry back faster than most potting soils, so they ask for more frequent waterings.
That's the whole reason coco gets its own rhythm.
The rhythm
Water the whole pot. Every watering wets the full root ball, with 10 to 20% coming out the bottom. Not a splash on top.
Let it get a little lighter. Lift the pot. You want it lighter than right after watering, but nowhere near the bone light pot soil is fine with.
Water again before it gets far. A small dry back is fine. A deep one is what gets you.
Change one thing at a time. If she wants more, water more often before you water more each time, and give it a full cycle before you judge.
Early in veg, with a small plant and small roots, watering every other day is a fair start, as long as the pot is getting lighter in between. As the plant grows and the room warms up, the gap shrinks. A big plant in flower may want water more than once a day.
Why the dry back can't run long
When coco dries far, the water leaves and the salts from your feed stay put. The further she dries, the stronger what's left gets. That's why a long gap in coco shows up as high runoff, burnt tips and swinging pH, even when the feed itself was fine.
The fix is timing, not a bigger drink. One big watering followed by the same long gap still lets it concentrate. Smaller, more frequent waterings keep the root zone even.
The other side matters too. Coco that never dries back at all, like a pot sitting in a tray that refills itself, leaves the roots without air. Root trouble in a pot that's always wet is an oxygen problem before it's a feed problem. A light dry back is what hands the roots their air.
Feed and pH
pH: coco runs lower than soil, about 5.8 to 6.2 going in. Soil fed from bottles runs about 6.2 to 6.8, so don't carry your soil number over.
Feed strength: start around 0.4 to 0.8 EC for seedlings, 0.8 to 1.4 in veg and 1.2 to 1.8 in flower. Those are safe starting lanes, not a cap. Let the plant and the bottle's own chart move you from there.
Every watering carries feed. In coco, plain water every other time leaves the plant short and can pull the root zone out of balance.
Reading runoff in coco
Runoff means more in coco than in soil, because coco doesn't buffer the way soil does. It's still a snapshot, though. One high reading after the pot ran unusually dry is usually a dry back spike.
Start watching when runoff sits about 0.5 EC above what you put in. It's worth acting on at about 0.7 to 1.0 above, but only when the gap climbs for 2 to 3 waterings in a row and the plant shows stress. Then tighten the timing first. If you need a reset, use a very light feed, half strength or less, for a watering or two, not gallons of plain water.
What not to do
Don't run coco on a soil schedule. Waiting days for a bone light pot is how salt stacks up.
Don't fix a high reading with a big plain water flush. Fix the gap between waterings.
Don't let it sit wet forever. A light dry back keeps air at the roots.
When it's something else
Watering a pot of soil, or a plant that's drooping: see How often should I water, and why is she drooping?
A high runoff number in soil: see My runoff number is high. Should I flush?
What water to use, and the pH meter itself: see What water should I use, and what pH should it be?
Keep going
Coco bags, soil bags and the feed and pH lanes for each: see our which soil bag shelf guide.
A light dry back, feed every time, one change at a time. The whole system for a steady grow is written down in the free Stability Playbook. Get the free Stability Playbook
More answers: all grow guides. Every shelf guide and maker feed chart: Grower Resources.