# Medium dries out within a day; water runs straight through or down the sides: likely causes and fixes

> Medium dries out within a day; water runs straight through or down the sides on cannabis is most often Root-bound in a pot too small, Underwatering or Dry, water-repellent medium (water runs straight through). How to tell them apart, the fix for each and what recovery looks like.

Also called: water runs right through, soil hydrophobic, dry pockets in pot, soil pulled away from pot.

Run the checker with this sign: https://genetixbay.com/knowledge/diagnose/?at=roots&s=medium-dries-fast

## Likely causes, most likely first

### Root-bound in a pot too small (Possible)

- Kind: Root zone; urgency: Deal with it this week
- Fix: Up-pot photoperiods into a container about 2-3x larger, loosening circling roots gently. Autoflowers: don't transplant; increase watering and feeding frequency instead. Small pots can still grow big plants with high-frequency fertigation (several feeds a day).
- Recovery: New white roots in the fresh medium within 5-7 days; daily wilting stops.
- Confirm: Look at the roots: Hydro: lift the net pot and look at the root mass in good white light. Containers: tip the plant out with a hand over the medium and look at the edges and bottom of the root ball. Healthy roots are white to cream with fine fuzzy tips. Brown roots whose outer layer slides off between the fingers leave a bare thread: rot. Firm, evenly tan roots with white tips in coloured solution are staining.
- Confirm: Lift the pot and check moisture at depth: Lift the pot right after a full watering to learn its wet weight, then lift before each watering. Water when it is clearly lighter (about half the added water gone). Push a finger or a moisture probe 5 cm (2 in) down. Heavy for 3-4+ days with droop: overwatering. Very light with limp papery leaves: thirst.
- Article: [Cannabis root problems: the master decision tree](https://genetixbay.com/knowledge/diagnosis/root-problems-decision-tree.md)

### Underwatering (Possible)

- Kind: Root zone; urgency: Act within a day or two
- Fix: Water slowly in 2-3 passes until 10-20% runoff, so the whole root ball wets. Water when the pot is clearly lighter, before the plant droops. Mild late-flower dry-back is a house-endorsed practice for some cultivars (Caplan 2019), but wilting is not.
- Recovery: Turgor returns within 1-6 hours of watering.
- Confirm: Lift the pot and check moisture at depth: Lift the pot right after a full watering to learn its wet weight, then lift before each watering. Water when it is clearly lighter (about half the added water gone). Push a finger or a moisture probe 5 cm (2 in) down. Heavy for 3-4+ days with droop: overwatering. Very light with limp papery leaves: thirst.
- Article: [Drooping cannabis: overwatering vs underwatering](https://genetixbay.com/knowledge/diagnosis/drooping-overwatering-vs-underwatering.md)

### Dry, water-repellent medium (water runs straight through) (Possible)

- Kind: Root zone; urgency: Deal with it this week
- Fix: Rewet slowly: small amounts every 10-15 minutes, or bottom-soak the pot for 20-30 minutes; a drop of plant-safe wetting agent helps peat. Don't let peat mixes go bone dry again.
- Recovery: Pot gains its normal wet weight and holds it for a day or more.
- Confirm: Lift the pot and check moisture at depth: Lift the pot right after a full watering to learn its wet weight, then lift before each watering. Water when it is clearly lighter (about half the added water gone). Push a finger or a moisture probe 5 cm (2 in) down. Heavy for 3-4+ days with droop: overwatering. Very light with limp papery leaves: thirst.
- Article: [Why does water run straight through or pool on top of my pot?](https://genetixbay.com/knowledge/answers/water-runs-through-or-pools.md)

## Note

Guidance, not a guarantee. The checker weighs common causes against what you tell it; confirm with the tests before you treat, change one thing at a time and watch the new growth.