Snake plants turn black because of root rot caused by damp soil around the roots, over watering or high humidity. Snake plants require well draining soil and pots with drainage holes to avoid root rot which turns the leaves black.
If your snake plant leaves have turned black keep reading for how to implement the best practices of care to prevent this happening and how revive your snake plant…
Over Watering Causes Snake Plants to Turn Black
The most common cause of snake plants turning black is due to over watering.
Snake plants are native to Africa where they grow in drought like conditions with infrequent rainfall.
If you are watering your snake plant more frequently then once per week then you are over watering your snake plant.
This is particularly true in Winter time when snake plants go seasonally dormant and stop growing, which reduces its demand for moisture so in the Winter months watering once per month (with a good soak to encourage health roots) is required to avoid root rot.
(If your snake plant is not growing read my article for the reasons why and how to solve it).
Too much water around the roots from frequent watering promotes the conditions for the fungal disease root rot which turns the snake plant leaves black.
Snake plants often turn yellow and droop as the first indication of over watering with black leaves indicating that root rot has occurred.
How to save it…
Scale back the watering. Snake plants should be watered with a cycle of soaking the soil and then allowing it to dry completely as this replicates the conditions its native environment.
Typically snake plants prefer watering once every two weeks but the best way to establish the correct watering frequency for your climate is if you feel the soil at the bottom through the drainage hole in the base to detect whether the soil is dry or moist.
(Read my article for how often to water snake plants in Winter).
If it is dry this is the perfect time to water, if it is still moist then wait till it dries before watering.
Once rot has set it, it can be very difficult to revive a snake plant.
So the best option is to cut back any sections of black from your snake plant and leave only healthy tissue as the black rot spreads and eventually kills the plant if left untreated.
Once the black infected part of the plant is removed and you have corrected your watering practices the plant has a chance of regrowing.
If there are significant section of you snake plant that has turned black then this can be very difficult to revive and its likely the plant dies back.
If there is any healthy tissue on the plant then I recommend taking cuttings for propagation.
Propagating snake plant from cuttings is very easy and has a high success rate. Watch this video for how to easily propagate your snake plant:
Slow Draining Soils
Snake plants have adapted to growing in naturally gritty soils that do not hold onto much moisture and drain very quickly.
If the snake plant is in ordinary potting soil then this is likely to retain too much moisture around the roots of your snake plant and cause the leaves to turn black.
It is important that snake plants are planted in soils that mimic the well draining characteristics of the soil in their native environment.
Snake plants thrive when they are planted in specially mixed succulent and cacti soil which is available from garden centers and on amazon.
Special succulent potting mixes have the exactly the right drainage characteristics for snake plants so that water infiltrates effectively to reach the roots yet drains away quickly to avoid root rot.
If you have a potting mix that stays moist for a long time after watering then replace the soil with some succulent and cactus soil to prevent further stress to the plant.
Even with the right watering frequency and well draining potting mix it is still important to cut out any black sections of leaf entirely to prevent any rot spreading and for the plant to recover.
However with significantly black snake plants it may be necessary to take any cuttings you can from any remaining green leaves for propagation.
Pots Without Drainage Holes in the Base Cause Water Stress
Snake plant leaves can turn black due to water stress because they are planted in pots without drainage holes in the base of the pot which causes water to pool around the roots.
If you snake plant is in a pot without drainage holes then re-pot it immediately to save it.
Pots without drainage holes in the base is not the only reason for snake plant leaves turning black.
- The use of saucer and trays. If you have a saucer or tray underneath your pot to prevent water from spilling then this should be emptied frequently to allow excess water to escape rather then pool around the base of your pot as this keeps the soil damp and causes root rot.
- Drainage hole clogged by roots or compacted soil. It is worth checking the base of your pot if you notice the soil draining slowly. Sometimes the drainage holes become clogged with thick roots or compacted soil. With succulent and cactus soil, the potting soil is less likely to be compacted and more likely to stay porous and well draining.
- Snake plants are often sold in the store as gifts with a decorative outer pot. This pot can prevent excess water from escaping and cause the soil to stay damp causing water stress and your snake plant leaves to turn black.
Snake plants require the soil to dry out between bouts of watering to prevent rot and the leaves turning black so it is important to plant your snake plant in the appropriate pot and ensure that excess water can escape after watering.
The same applies to snake plants that are water stressed for any other reason, in that you should cut away any black leaves back to healthy tissue and propagate from cuttings if necessary.
Humidity Slows Water Loss from Leaves and Causes Black Leaves
Snake plants are native to hot and dry environments and prefer to be in rooms of low humidity.
Humidity can slow the rate of transpiration (water loss) from the snake plants leaves, which is the primary way that snake plants regulate their moisture levels.
Less transpiration due to high humidity can contribute to the water stress that causes snake plants to turn black.
Higher levels of humidity may not be just because of the climate, but also due to:
- Watering onto the leaves or misting the leaves. It is contrary to the snake plants preferred dry conditions to mist the leaves. Water snake plants at the base of the plant rather then overhead to prevent creating a humid micro-climate.
- Humid rooms of the house. Snake plants generally do not like to grow in steamy rooms such as the bathroom or kitchen with lots of moisture in the air. Locate your snake plant in a dryer rooms.
- Humid climates. Snake plants can struggle to grow in climates with high levels of humidity, so find a breezy location for your snake plant if it is possible.
Ensuring your snake plant is in a room of lower humidity can help the plant recover from rot and prevent any further damage to the leaves.
For more information read my article how to revive a dying snake plant).
- Snake plants turn black because of root rot when there is too much moisture around the roots caused by over watering, slow draining soils or pots without drainage holes in the base. High humidity can also contribute to the leaves turning black.
- Scale back the watering, replace the soil with succulent and cactus soil and ensure the snake plant is in a pot with good drainage.
- Locate the snake plant in a room with lower humidity and avoid steamy bathrooms or kitchens.
- Cut away any black rot from your succulent to prevent the rot from spreading and propagate from healthy cuttings if necessary.