Aloe vera is a hardy, succulent, semi-tropical plant native to North Africa and the SW Arabian Peninsula, which can tolerate quite harsh conditions. It will grow in poor soils in hot, dry sunny locations with very little water, but can also tolerate dappled sun or part shade, which allows it to be grown successfully as an indoor plant when located near a window with bright natural light.
When grown outdoors, Aloe vera plants will flower. They produce clusters of dangling tubular yellow or orange flowers on long stalk which grow from the centre of the plant around early spring. They tend not to flower when grown indoors as houseplants.
How Healthy Aloe Vera Plants Should Look
Healthy Aloe vera plants are grey-green or blue-green in colour, with vibrant green young leaves.
The Symptoms of an Unhealthy Aloe Vera Plant
When Aloe vera plants are subjected to unfavourable conditions, they may show some of the following signs:
- Leaves become pale in colour, the green colour fades to a straw yellow colour which eventually turns light brown.
- Leaf tips darken and dry out.
- Leaves dry out and wither.
- Leaves become soft and mushy, and begin to rot.
What Makes Aloe Vera Plants Unwell and How to Prevent It
When plants get exposed to conditions they don’t like, they become stressed, and start showing signs that they’re unhealthy.
What are the conditions that can stress Aloe vera plants?
When Aloe vera plants are overwatered, the leaves will fade in colour, yellow, brown off and eventually rot away.
Testing for overwatering is quick and easy:
- If the plants are in the ground, push a garden hand trowel into the soil and check if the soil is waterlogged.
- If plants are growing in pots, lift up the container to check the weight, if it feels excessively heavy it’s because the growing medium is saturated with water.
Aloe vera plants don’t need much water. If they’re growing in containers, water once a week in summer and once every two weeks in winter. All tropical and subtropical plants don’t like too much water when it’s cold, as it rots their roots.
What about rainfall?
When growing Aloe vera in pots or containers outdoors, don’t leave them out in the open in winter where they will be exposed to rainfall, place them in a location that will shelter them from the rain. An ideal place is near a sunny house wall where the roof overhangs and protects them from the rain. I have mine containers of aloe vera growing against a west facing wall, where the afternoon winter sun warms the wall and elevates the winter night temperature around the plants.
Aloe vera plants growing in the ground will be fine if they’re subjected to rain as long as the soil drains well in winter. Heavy clay soils should be amended before planting, the soil in the planting area needs to be mixed with compost (about 25% by volume) to improve drainage.
Can the size of pot make a difference?
Overpotting a plant can cause waterlogging! Aloe vera plants, just like all other succulents, need to be grown in a soil mixture drains freely when grown in pots. Please don’t use garden soil in pots, that becomes mud in containers when it gets wet! Even when using a well draining growing medium (potting mix), if the pot is too large for the plant, the plant’s small root system isn’t capable of taking up all the water, which results in the growing medium staying excessively wet for an extended period of time. This has the same effect as overwatering on the plant.
Aloe vera plants prefer to be snug in their pot with a dense root mass, so when transplanting them, move them up to the next sized pot only, don’t put them in an overly large pot. Give the plant around 3-4 cm (1-1 ½”) of space all round the sides in the new pot. Transplant Aloe vera plants every two years to freshen to growing medium and aerate the roots.
2. Sudden Change in Growing Conditions
Aloe vera plants may be very tough and adaptable, but any plant will get stressed if the growing conditions are changed suddenly.
Here are some examples of sudden changes in growing conditions that can severely stress a plant:
Indoors to Outdoors – If an plant has been growing indoors for quite a while, putting it into outdoors in harsh direct sun will usually burn the leaf tips. Plants need to be ‘hardened off’ by gradually exposing them to increasing levels of sunlight from shade to dappled sun the full sun over several weeks.
Unexpected Drought Conditions – plants dependent on rainfall can become moisture stressed during extended heatwaves which lead to drought conditions. This condition is easy to recognise as leaf tips will usually be burnt, they will be dark brown in colour, and whole leaves may be completely dried out and withered at the base of the plant.
Abrupt Seasonal Changes – when plants are adapted to warm weather, a sudden shift to very cold weather as the seasons change, such as an unseasonal freezing cold night or sudden frost can acutely stress plants. Cold affected plants will usually display a yellowing of the leaves, and frosts will burn the tips of Aloe vera plants.
How To Save a Sick Aloe Vera Plant
When an Aloe vera plant looks unhealthy, it doesn’t take much to bring it back to health if action is taken early enough. Plants are quite capable of recovering if the conditions causing the stress are removed, and growing conditions are corrected and returned back to normal.
The plant pictured below was overwatered and exposed to a sudden seasonal weather shift which brought erratic weather changes and very cold nights after a long warm spell. This Aloe vera plant was completely yellowed, and the outer leaves had turned a light brown colour.
To save the plant, it was placed in a greenhouse where it wouldn’t be watered by gardeners, receive rainfall, or be exposed to cold night temperatures.
After two weeks, there are signs of recovery as the inner leaves start to green once again and take on their natural colour.
Restoring conditions which assist with plant recovery are fairly straightforward.
- Overwatered plants – stop watering, and place them under cover away from rainfall.
- Overpotted plants – transplant into a smaller pot, so the potting medium will dry more easily between waterings.
- Drought-stricken plants – remove burnt leaves, do not remove leaves with burnt tips, water plants to restore soil moisture, also consider using seaweed extract as it acts as a root growth stimulator and also helps stressed plants recover.
- Cold-stressed plants – place pots near a wall that receives midday or afternoon sun to keep overnight temperatures higher around the plants, water less often in winter, keep the plants out of the rain, and remove any saucers underneath that retain water.
Given time, the plants will green up on their own and totally recover, all they need is a little help!
You might also like these other articles on Aloe vera plants:
- Identifying and Growing Edible Aloe Vera
- How to Make Aloe Vera Gel from Fresh Aloe Vera Leaves
- How to Grow the Medicinal Aloe arborescens