Did my aloes sunburn?

Question

Today has been the first sunny day in a long while, and some of my aloes sat in the sun of a south-facing windowsill for the first time. Two of them were in an office before, never getting direct sunlight.

When I came home, I noticed a new brown tinge had appeared, most pronounced at the base of their new leaves, and less elsewhere.

I learned recently that aloes need to acclimatise in order to stand full sun, but I wasn't expecting such a reaction on the first day.

My questions are:

• Is the damage permanent?
• If not, where should I place them to make them recover, and for how long?
• What schedule should I follow to make them acclimatise to the windowsill?

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Pictues below. The brown tinge looks much more pronounced to the naked eye than in the pictures.

The two plants on the right come from an office setting where they received dim indirect light, until I brought them home last week. Today was their first exposure to full sun. The pup is Aloe Variegata.

Detail of the browning:

Answer 1

Haworthia do not like direct sun, especially when kept as a houseplant - I agree with the ID of Haworthia attenuata, so yes, it does need a different situation from a true aloe, so somewhere with good light but not direct sun.

Not sure what your aloe is either - maybe A. mitriformis, and they do cope with sun. If its winter where you are, I'd be surprised if the sun caused a problem, but if the plant was exposed all day to unexpected sunlight, it might have caused a problem, though that's difficult to detect from the photos.

Assuming sunlight has caused the trouble, stand it in sunlight for increasing periods, rather than leaving it exposed all day, so give it a couple of hours of morning sun, then move it, and increase its exposure over time. As for the small plant in your images, I'm not sure what that is, but you'd need to be careful about sun exposure just because its small, so a similar arrangement - a small but increasing amount of exposure over time.