Watering schedule by container type

“Watering schedule” is misleading — you should never water on a fixed schedule. Water based on what your terrarium needs. Here’s how to read those needs by container type.

Closed terrariums

Rule: Almost never water. The water cycle handles it.

When to water:

• No condensation at all for 48+ hours
• Substrate pulling away from glass
• Plants starting to wilt

How much:

• 1-2 tablespoons of distilled water, poured down the side
• Wait 24 hours
• Repeat if needed (rarely needs more than 1-2 doses)

What to use:

• Distilled water (best)
• Rainwater (excellent)
• Filtered water (acceptable)
• Avoid tap water (mineral buildup)

Open terrariums

Rule: Check weekly, water when top of substrate feels dry.

When to water:

• Insert finger 1/2 inch into substrate
• If dry, water
• If still moist, wait

How much:

• Until you see slight drainage into the bottom layer
• Stop before standing water

When:

• Morning is best (water evaporates during day, less mold risk)
• Avoid evening (water sits overnight in cooler temps)

Bioactive terrariums

Rule: Maintain humidity for cleanup crew. Less frequent but more thorough.

For closed bioactive:

• Same as closed, but add a small amount of water if springtails/isopods are dying

For open bioactive:

• Water when substrate starts to dry
• Spray leaf litter to keep isopods hydrated
• Mist more than non-bioactive (microfauna need moisture)

Seasonal adjustments

Summer

• Higher temperatures = faster evaporation
• Closed: check fog cycle weekly
• Open: water more frequently (every 3-5 days vs 7-10)

Winter

• Indoor heating = very dry air
• Closed: monitor for over-drying
• Open: water less often BUT mist more (heating dries leaves)

Spring/Fall

• Plant growth cycles
• May see increased water needs as plants grow

Signs of overwatering

• Standing water in drainage layer
• Soil surface stays wet for days
• Mushy stems
• Yellow leaves
• Mold growth
• Fungus gnats

If you see these: open the lid, let it dry out, reduce future watering.

Signs of underwatering

• Substrate pulling from glass
• Crispy leaf edges
• Wilting plants
• No condensation in closed jar
• Slow growth

If you see these: water thoroughly, monitor for recovery over 24-48 hours.

The universal rule

When in doubt, don’t water. Most terrarium plants tolerate being slightly dry better than being slightly wet. Overwatering causes more problems than underwatering.

The cheat sheet

Container	Frequency	Amount	Check method
Closed	Rare (monthly+)	1-2 tbsp	Condensation cycle
Open	Weekly	Until slight drainage	Finger in substrate
Bioactive closed	Rare	1-2 tbsp	Springtail activity
Bioactive open	Weekly	Until drainage	Substrate moisture

For more, see our humidity guide or ask the Discord.