Aloe vera

Light and exposure

Aloe wants the maximum of light. The best spot is the ledge of a south or south-west facing window. The more light it gets, the more it stays compact, stocky and coloured, sometimes tinged with pink or brown at the tips, a sign of good exposure. In the light, the sap flows and the plant stays firm.

In a dark corner, aloe grows leggy: the leaves lengthen, soften and spread apart, and the rosette loses its shape. In our winter light, weak from November to February, give it the sunniest window in the house. Be careful, though, of putting it back into full sun too abruptly in spring, which can scorch the foliage: reacclimatise it gradually.

Watering

This is the decisive point. Water thoroughly, then let the substrate dry out completely before starting again. In practice, this comes down to watering every ten to fifteen days in spring and summer, and barely once a month, or even less, in winter. Push a finger into the soil: if it is still cool, wait.

Always empty the saucer and never water into the heart of the rosette, where standing water rots the crown. In our damp climate, the classic mistake is to water in winter as in summer. Soft, yellowed and translucent leaves at the base signal excess water and the beginning of rot: this is far more serious and frequent than a lack of water, which aloe takes without flinching.

Soil and repotting

Aloe demands a very free-draining substrate. Use a special potting mix for cacti and succulents, or mix ordinary compost with a third of coarse sand or perlite. A terracotta pot, which lets the root ball breathe and dries faster than a plastic pot, is ideal here.

The pot must have drainage holes without fail. Repot in spring every two or three years, or when the offsets fill the pot. Choose a container barely larger: a large volume of soil stays damp too long and puts the roots in danger.

Temperature and humidity

Aloe likes 18 to 25 degrees in full growth and tolerates heat without a problem. It withstands coolness down to 10 degrees, but survives no frost: below 5 degrees, the water-filled leaves freeze and turn to mush.

Unlike most green plants, aloe loves the dry air of Belgian central heating, which reproduces its native climate. The real trap of the cold season is therefore not the dry air but the damp cold: never leave it in an unheated conservatory or near an icy single-glazed window, especially if the soil is damp.

Pruning and upkeep

Aloe is not pruned as such. You simply remove the dried or damaged outer leaves by cutting them at the base, flush with the stem, with a clean knife. It is always the lower leaves that age first, that is normal.

To harvest gel, cut a mature leaf from the outside of the rosette and first let the yellow latex, irritant, drain away before opening the leaf. The plant heals over on its own at the cut. Never remove too many leaves at once, the plant needs them to feed itself.

Pests and diseases

Aloe is little prone to disease when you don’t overwater it. The real danger is rot of the roots and crown, caused by excess water and a substrate that doesn’t drain: soft leaves, a brown and soft base, a musty smell. In that case, take out the root ball, cut away all the rotten tissue, let the wound dry for a day or two and repot in dry conditions.

As for pests, watch for mealybugs, small white cottony clusters in the axils of the leaves, more frequent in winter. Remove them with cotton wool soaked in diluted methylated spirits. Red spider mites remain rare on this succulent.

Propagation

Aloe is very easily propagated by its offsets, those small rosettes that grow at the foot of the mother plant. At the spring repotting, gently detach an offset with a few roots, let the cut dry for a day or two so it heals over, then plant it in a barely damp free-draining substrate.

Wait a week before the first watering, the time for the roots to mend: an offset planted and watered straight away often rots. Sowing exists but remains slow and reserved for enthusiasts; dividing the offsets is far simpler and quicker.

Toxicity

The translucent gel from the inside of the leaves is used on the skin, but the yellow latex just under the rind is a powerful laxative and causes digestive upset if swallowed. The plant is toxic to cats and dogs. Do not eat a leaf without knowing how to separate the gel from the latex.

Month-by-month care calendar

Green Hub tips

• Aloe’s worst enemy here is not drought but excess water in winter: when in doubt, don’t water.
• A terracotta pot and a special cactus substrate dry fast and protect the roots from rot.
• Never water into the heart of the rosette: water sitting there rots the crown and kills the plant.
• Before using the gel on skin, let the yellow latex under the skin drain away, it is irritant and laxative.