How often should I water my terrarium?
The water requirements for open and closed terrariums are quite different, as different types of plants often have very different care requirements. For this reason, you should always aim to have plants grouped together that have similar water and lighting needs (for example, succulents and cacti go together, and ferns and fittonias go together. Avoid planting succulents with ferns, for example, if you want a long-lasting plant arrangement).
If you're not sure what the natural conditions are of your plant, our top tip is to figure out where that plant is found in nature. Deserts? The plant will like plenty of sunlight and very little water. Woodlands? Low light and humid conditions. Rainforests? Humid conditions, indirect/dappled sunlight, warmth.
Open Terrariums
For open terrariums that include succulents, cacti, haworthia and other plants that are found in the desert, make sure your terrarium is placed in a bright spot and water it only when the soil dries out. This might be once a month in winter, or twice a month in warmer months.
For open terrariums that include plants such as fittonias and ferns, make sure to keep them in shadier areas that receive indirect sunlight. Don't let the soil dry out, but make sure not to make it too soggy. Depending on how dry the air is in your home, you can mist the plants once a week, or keep them in a humid environment such as a bathroom.
Closed Terrariums
Closed terrariums usually recreate self-sustaining conditions that don't require any watering at all once the terrarium has been established.
When you first plant your terrarium, add a little bit of water at a time. A spoonful will do, as the soil usually has enough moisture in it.
If you don't get any condensation building up in the following couple of days and the air in the terrarium seems quite dry, add another spoonful of water until you see evidence of the water circulating via the process of condensation, where it embarks on a continuous self-watering journey.
To prevent moulding and smells (if you haven't included springtails) you might want to remove the top every few weeks to air it out. You might also want to invest in a pair of terrarium scissors to prune back your plants for bushier growth, or if you'd like to keep your terrarium trim rather than 'wild' and full.