Brown Tips on Leaves: Five Causes and How to Tell Them Apart

Brown crispy tips are the most common thing people notice and the most commonly misdiagnosed. Search once and every answer says humidity, so people buy a humidifier and the tips keep coming.

Humidity is one of five causes and it is not usually the main one. Here is how to tell.

Look for the yellow halo first

Check whether there is a thin yellow band between the brown dead tissue and the healthy green.

Yellow halo present. The plant is actively withdrawing from that tissue. Points at a water or nutrient issue: inconsistent watering, salt buildup, or a shortage.

No halo, brown starts abruptly. Points at physical damage: dry air, a draught, heat from a radiator, or a chemical burn from fertiliser or fluoride.

Then check the soil two inches down, because that separates most of what is left.

The five causes

1. Inconsistent watering. The most common cause by a distance. Letting a plant dry out hard, then soaking it, then letting it dry hard again. Tips die during the dry swings. Soil will sometimes be wet, sometimes bone dry.Most likely
2. Fertiliser salt buildup. Look for white or yellow crust on the soil surface or pot rim. Flush the pot at a sink for a couple of minutes and stop feeding for a while.Check the rim
3. Tap water chemistry. Fluoride, chlorine and hard water minerals accumulate in leaf tips, which is where the plant deposits what it cannot use. Spider plants, dracaena, calathea and prayer plants are the sensitive ones.Sensitive species only
4. Low humidity. Genuine for ferns, calathea, maranta, alocasia and other tropicals, especially in a heated house in winter. Usually accompanied by curling.Winter and tropicals
5. Heat or draught. A radiator underneath, a heating vent blowing on it, or a cold draught from a door. Damage is often worse on the side facing the source.Check the position

The tap water one is worth taking seriously

If you have a spider plant, dracaena, calathea, maranta or a prayer plant with brown tips and you have already fixed your watering, the water itself is the likely culprit.

These species are unusually sensitive to fluoride, which is added to municipal water in much of the United States, Canada, Australia and parts of the UK. They cannot excrete it, so it concentrates at the leaf tips and kills the tissue there.

The fix is filtered water, rain water, or distilled. Letting tap water stand overnight helps with chlorine but does nothing for fluoride, which does not evaporate. That is a widely repeated tip that only half works.

Should you cut the brown bits off?

Yes, cosmetically. It will not harm the plant and it stops the leaf looking worse than it is.

Use clean scissors and cut just inside the brown, following the natural shape of the leaf rather than straight across. Leaving a hair's width of brown looks better than cutting into green tissue, which creates a fresh wound that browns again.

The important thing: trimming is not treatment. A tip that has died stays dead. Judge whether you fixed the cause by whether new leaves come out clean, not by how the old ones look.

What to actually change

Start with watering rhythm, because it is the most common cause and it costs nothing. Water when the soil is dry at depth, thoroughly, every time. Consistency matters more than frequency.

Then flush the pot if there is any crust on the surface, and lay off fertiliser for a month or two.

Then, if it is one of the sensitive species, switch to filtered water for a few months and see whether new growth comes in clean.

Humidity is worth addressing last unless the plant is a fern or a calathea, in which case move it up the list. Group plants together, use a pebble tray, or run a humidifier. Misting does very little and leaves water sitting on leaves overnight, which encourages fungal spots.

Change one thing at a time and give it a month. New growth is your answer.

Different species have very different tolerances here, and a brown tip on a snake plant means something quite different from a brown tip on a calathea. Photograph the plant and the affected leaves and Identium will tell you the species and which of these it is actually prone to.