Brown edges are the most common complaint with a rattlesnake plant. The damage is permanent on the leaves it has already hit, which makes it feel worse than it is. Something in its conditions needs to change, and the next leaves will show whether you found it.

The rattlesnake plant is Goeppertia insignis. NC State Extension lists its former names as Calathea insignis and Calathea lancifolia, and most shops still sell it as a calathea. NC State rates it high maintenance and says it can be difficult to care for because of its humidity needs.

What the plant expects

FactorWhat the sources say
LightLimited sun to bright shade; tolerates early morning or diffused sun, not full sun (NC State). Bright spot out of direct sun (RHS)
WaterUniformly moist, but not wet, in spring and summer; less in winter (NC State). Never let the compost dry out completely (RHS)
HumidityHigh: wet pebble tray or a humidified room (NC State). Kitchens and bathrooms suit calatheas (RHS)
Temperature18–24 °C (65–75 °F); no drafts or sudden changes (NC State). RHS: 16–21 °C (61–70 °F), away from radiators
MixWell-drained, peaty mix (NC State)
FeedingBalanced fertilizer monthly in spring and summer; less in winter (NC State)

Brown edges usually trace back to one of these rows going wrong.

The five common causes

1. Dry air

This is the first suspect. The RHS says browning of calathea leaf tips and edges is usually a result of low humidity. Iowa State Extension calls low humidity the most likely cause of brown tips and edges on any houseplant, especially in winter.

University of Georgia Extension notes that relative humidity of 10 to 20 percent is typical of most homes. It says new plants placed in air that dry lose water rapidly. University of Maryland Extension adds that most indoor spaces lack humidity, particularly in winter.

Points to dry air: browning that started or worsened when the heating came on, on a plant whose mix stays evenly moist.

2. Uneven watering

Iowa State says letting plants dry out too long between waterings browns leaf tips and edges. NC State asks for uniformly moist mix, and the RHS says never to let the compost dry out completely.

Points to watering: mix that dries hard between waterings, a pot that feels very light, or browning after a missed watering.

Too much water causes different trouble. The RHS warns that roots left standing in water can easily rot. UF/IFAS lists wilting from drought stress or root pathogens, and says to check the roots. If leaves wilt or yellow while the mix is wet, look at the roots before anything else. Our calathea drooping guide covers that check.

3. Chlorine and fluoride in tap water

University of Georgia Extension names rattlesnake plant among plants susceptible to fluorine and chlorine in irrigation water. Iowa State lists prayer plant and calathea among species sensitive to chlorine and fluoride over time. UF/IFAS gives dead spots near the leaf margins as the symptom of fluoride toxicity in calatheas.

The sources differ on the fix:

  • The RHS says all houseplants prefer rainwater. It says calatheas tolerate tap water left to stand for at least 24 hours so the chlorine evaporates.
  • Clemson Extension also suggests letting water stand at room temperature for 24 hours.
  • University of Georgia suggests letting water stand for several days so that some chlorine and fluorine are released.

Standing water is mainly a way to lose chlorine. If browning continues, a switch to rainwater or distilled water is a cleaner test. Our calathea water quality guide explains how to check your supply and test one change at a time.

4. Salts from fertilizer

UF/IFAS lists leaf margin or tip necrosis in calatheas caused by low pH or excess fertilizer, particularly high manganese. Iowa State says salts build up when too much fertilizer is applied.

Points to salts: a white to grey crust on the mix surface or pot rim, which Clemson says is a sign of salt buildup, and a habit of feeding often or through winter.

Clemson’s steps to reduce salt injury:

  1. Use rainwater when possible.
  2. Drench the pot periodically to leach salts out.
  3. Empty the saucer after watering.
  4. Do not over-fertilize.
  5. Scrape off salt crusts and add fresh mix.
  6. Repot periodically in new potting mix.

5. Sun, cold or drafts

NC State says the rattlesnake plant does not tolerate full sun, drafts or sudden temperature changes. Clemson lists hot, dry air as a cause of brown tips and margins. Maryland advises keeping indoor plants away from heating and air-conditioning sources.

UF/IFAS warns that temperatures below 13 °C (55 °F) may cause chilling injury in calatheas. Clemson notes that cold water or water splashed on leaves can leave white or straw-coloured spots on some plants.

Points to position: browning on the side facing a window, heater or door, or damage that appeared soon after a move.

Rule out pests

Clemson lists insect feeding among the causes of brown tips and margins, so check. The RHS says speckled, yellowing or silvery leaves with fine webbing may be a sign of red spider mites. Look under the leaves with a hand lens. Our spider mite guide covers confirmation and treatment.

What to do, in order

  1. Check the mix by pushing a finger about 2.5 cm (1 in) below the surface, as University of Georgia Extension suggests. If it has dried hard, water thoroughly and check more often.
  2. Measure the air. Put a hygrometer beside the plant for a few days. If the air is dry, NC State suggests a tray of wet pebbles or a humidified room. Maryland suggests grouping plants or running a humidifier.
  3. Move it out of direct sun and away from heaters, vents and draughty doors.
  4. Review feeding. Feed monthly in spring and summer only, as NC State advises. Flush the pot if you see a salt crust.
  5. Change the water to rainwater or distilled water if browning continues once the first four are right.
  6. Wipe the leaves. NC State notes that dust slows photosynthesis and suggests cleaning leaves with a clean cloth.

Change one thing at a time where you can. Then you will know which fix worked.

Trimming and judging progress

Brown tissue does not turn green again. Iowa State says trimming the brown parts improves appearance, but new browning will occur if the cause is not addressed. Follow the leaf’s natural outline and cut only dead tissue.

Judge your changes on the next leaves to unfurl. If they stay clean, you found the cause. If they brown in the same way, work down the list again.

Folding at night is normal

NC State says rattlesnake plant leaves fold in half in the evening and reopen at sunrise. That movement is not stress. See our calathea leaf movement guide. Leaves that stay rolled during the day are a different signal, covered in the calathea curling leaves guide.

The ASPCA lists Calathea species as non-toxic to dogs, cats and horses.

References