Aloe vera plants are about 95 percent water--they store an enormous quantity of liquid in their leaves and roots. The high moisture content contributes to aloe's reputation as an all-purpose healer, especially suited for use to soothe burns and scalds. The most common error made by owners of aloe plants grown in containers, indoors or out, is overwatering their aloe plants. Aloe will thrive when its soil is allowed to dry out but will languish and even suffer from rot if the soil is kept too wet. It's much harder to overwater in-ground aloe since they have access to an extensive drainage system, but you'll often find that in-ground aloe needs no extra water from you to survive; natural rainfall is enough.
Poke your finger about an inch into the aloe plant's soil to determine whether it's dry beneath the surface or not. If the soil is still moist, come back a few days later and check again. If the soil is dry, it's time to water your aloe plant.
Pour just a cup or two of water into the pot with the aloe plant. The aloe only needs this minimal quantity of water during winter because this is its dormant season.
Palpate the aloe plant's leaves regularly. If the leaves feel mushy instead of firm near the central stem, you are overwatering; reduce the amount of water you're giving, along with the frequency, until the leaves firm up again.
Other Times of Year
Poke your finger about an inch into your aloe plant's soil every few days. When the soil is completely dry an inch deep, it's time to water your aloe again.
Pour water into the aloe plant's pot until the soil is well saturated.
Pour off any standing water that collects in the aloe plant's overflow tray immediately. An aloe plant should never be left in standing water.
Wait until the plant's soil is completely dry again--use your finger to check below the surface, as directed in Step 1--before watering again.