Aloe Barbadensis-Miller is probably the most maintenance free plant or crop to grow. It has no pest problems and even goats don't eat it. Keeping plants weed free is advisable but beyond that there is little that needs to be done. There are however methods that will help to produce healthier plants and a more abundant harvest.
Growing for your own use
The plant on the right is fully grown. It is over one metre tall and it's outer leaves are up to 90 cm long when picked. It is growing in Titirangi in Auckland with five other plants of approximately the same size. When planted they were about 20cm tall and they reached their full size in the second Summer after planting. As you can see in the picture a number of pups (plant-lets, root-shoots) have grown from the root. This is their natural method of propagation. A healthy plant will deliver about 4 - 6 pups every one or two years.
The soil bed was built up about 30cm to allow drainage in the winter months.
Titirangi, like much of Auckland, has a clay base about 20 cm beneath the top soil. Clay does not allow for good drainage so the area needed to be raised to allow the rain water to escape the roots of the plant. Aloe Vera does not like wet feet. The roots can not sit for prolonged periods in wet soil. They will eventually rot. It does, after all, have it's origin in tropical and arid environments. (Northern Africa originally however thrived in tropical climates when relocated by Arab traders around 600BC )
Generally there is no need to water an Aloe plant - they are remarkably resilient - however a slight watering once weekly during dry months is good. I water using Aquaticus Organic Garden Booster (see pic) mixed to it's strongest recommended dilution (50mil/Litre). Available at most garden centres. Just a light shower from a watering can once a week. It wont hurt to over water as long as the soil dries out.
So - you have planted a small plant-let - now sit back and be patient.
Growing for Fresh Leaf supply - Five plants or more.
Additional to the above you will need to bear in mind that harvesting leaves can be a difficult job if you have positioned the plants too close together. A mature plant will have a spread of about 70cm to one metre. You need room to separate (harvest) the leaves.
The adjacent diagram is a time tested guide to planting your Aloe crop. (enlarge).
Mature plant approx 1 metre tall with leaves ranging from 60cm to 90cm in length ready to pick.