This is much too late to answer your question but ideas might include most mints (there are several common ones), basil (again, several types), thyme, and so on. I believe the herb idea is close to perfect because herbs on the whole are easy to grow, requiring only sunlight or very bright light for at least six hours per day or thereabouts, warm temps, a bit of water now and again, have varied fragrances even within the same general species, and are edible. Additionally, small planter's/growers pots of herbs are available at almost any decent nursery and many can be grown quite easily from seed. Also, nearly all herbs can be grown inside or outside.

Much better idea for you to try with your munchkins other than the standard green bean in a pot exercise.

I don't know whether my suggestion is going to help you now or not as I'm a bit late to it, but still contributing it here with a hope.

I would like to suggest you to have allotted one plant to care for each student. You have to let them know how to take care of their plants and help them do it on a regular basis. Obviously, after a few days, they will get used to the idea and will be ready to do it on their own.

The intention behind allowing each kid with a plant is to bring them with more responsibility and enthusiasm towards what they are doing.

I'm a maids trainer and now working with a housekeeping company in Dubai known as HousekeepingCo. Whenever I conduct basic gardening training sessions for the housemaids and nannies, I often instruct them to create this kind of habit among the kids they are taking care of.

Please let me know if you need anything more from my side.

Regards,

Anna M

try any of these

Argyroderma testiculare. ...

Baby Rubber Plant. ...

Bunny Ear Cactus. ...

Century Plant. ..