Early caution signs
Wilting
The plant looks thirsty even though the medium is wet
Dark green
Leaves go a richer green than the rest of the crop
Crepeing
Leaf tissue thickens and feels like crepe paper
Yellow light
Those signs mean the root zone is already rich. Stop adding fertilizer and flush
Why salts pull water out
Normal flow: Plants keep a higher internal salt level so water moves inward.
Reversed flow: When the outside solution is stronger, water leaves the plant and tissue collapses.
Speed: A true overdose can wilt and crinkle tissue within hours.
Dry-back trap: A medium that dries hard can concentrate leftover salts two or three times above the original feed.
Rescue and maintenance flush
Plain water
Run enough clean water through soil or soilless mix to dilute the salt load
Hydro reset
Drain the reservoir, run a cleaner overnight if you use one, drain again, then refill with fresh water and a milder feed
Monthly habit
A periodic root-zone clean prevents the slow pile-up that looks like a mystery deficiency
Strength cap
Be wary of solutions stronger than about 1200 ppm (EC 2.4 mS)
Check pH before adding more
Lockout first
Many deficiency looks are precipitated minerals from a pH or ratio problem, not an empty bottle
Correct water
Irrigate with pH-adjusted water before you stack another nutrient
Watch new growth
Slightly damaged tissue may recover in three to five days. Necrotic tissue will not
Calcium exception
Calcium is poorly mobile, so old damage stays even after the feed is fixed
Foliar rescue rules
Mild only
Foliar feeds stay around 250 to 500 ppm (EC 0.5 to 1.0 mS) at pH 6.0 to 6.2
Soft water
Purified water enters the leaf better than hard water
No flower spray
Foliar feeding in bloom hurts flavor and helps mold
Timing
Spray in the morning, never in darkness or within three hours of lights out. Calcium is a poor foliar fix