Drybacks: How Dry Is Too Dry?

In coco we let pots dry back to about 50–60% between feeds — light, but never bone dry. Then we feed with about 25% runoff. That rhythm keeps the root zone steady and lets each feed wet the whole pot.

Dryback is the water the pot loses between feeds. Lift a pot right after a feed and again before the next one, and you'll quickly learn what a 50–60% pot feels like.

After transplant

Right after transplant we run hard drybacks on purpose:

1. Give three heavy feeds, with a hard dryback after each one. This takes about 5–7 days.
2. Move to daily feeds.
3. Once pots are hitting about 50–60% dryback by lights off, add a second feed each day.

Why bone dry is too dry

A bone-dry pot is hard to rewet. The next feed can run down a channel and out the bottom while part of the root zone stays dry. The salts left behind also concentrate as the pot dries, so root-zone EC climbs even though your CropSalt mix hasn't changed. The plant then looks like it needs a different nutrient when it really needs a better watering rhythm.

If pots are drying past 60% or runoff EC keeps climbing, start the first feed earlier or add a feed. Hot, dry rooms pull water faster, so run your numbers through our VPD calculator when water use jumps.

What we avoid

• Steering or stacking EC with dryback. We don't push drybacks harder to stack EC with CropSalt. We've seen it crash root-zone pH. The goal is a stable root zone, not a high EC number.
• Hard drybacks right before chop. Keep the pots on their normal rhythm through the finish.

The exception is a crop that's truly underfed, with runoff pH rising: raise the complete A+B mix in steps, allow a little more dryback, and ease back as runoff pH corrects.

Peat and rockwool

50–60% is our coco number. Peat and rockwool hold water differently, so learn their wet and dry weights on their own. In peat we run feed/feed/water with about 25% runoff. In every medium the rule is the same: let it get light, never bone dry.