How do I keep plants alive while I am away?

Watering solutions for a week or two away, ranked by how long they last and how much they cost.

Difficulty: beginner
Time: 45 min
Read: 2 min

Short answer

For up to a week, water thoroughly, move plants out of direct sun and group them together. For longer, use a capillary mat or wicks into a water reservoir. Grouping plants and reducing light does more than most people expect, because it slows how fast they use water.

Plants die while you are away from drying out, and the fix is either supplying water gradually or reducing how fast they use it. The second is free and surprisingly effective, which is why it comes first.

What you'll need

Trays
Capillary matting (optional)
Cotton wicks or string (optional)
Self-watering spikes (optional)

Step by step

Water everything thoroughly the day you leave.Until it runs from the bottom of each pot. Then let them drain — standing in water rots roots.
Move plants out of direct sun and away from radiators.Reducing light and heat slows transpiration considerably, which extends how long the water lasts.
Group plants together.They raise humidity around each other, which reduces water loss. Free and genuinely effective.
For up to a week, that combination is usually enough.Most houseplants tolerate a week if watered well and moved somewhere cooler and shadier.
For longer, stand pots on a capillary mat with one end in a water reservoir.The mat wicks water up continuously. It is the most reliable method for two weeks or more.
Alternatively run cotton wicks from a water container into each pot.One end deep in the compost, the other in a container of water set slightly higher. Test it for a day before relying on it.
Use self-watering spikes or bottles for individual large pots.They vary a lot in how fast they release. Test for a couple of days before you leave.
For outdoor pots, move them into shade and group them, or ask someone.Outdoor containers dry out far faster than indoor ones. For more than a week, a person is usually the only reliable answer.

Tips

Test any watering system for two or three days before you actually go. Several release water far faster or slower than expected.
A bath or sink with a few centimetres of water and plants standing on an upturned tray works as an improvised capillary system.
Cutting back soft growth and removing flowers before you go reduces water demand noticeably.

Common mistakes

Leaving plants standing in water — It rots the roots within days, which kills them faster than drought would have.
Leaving them in bright direct sun — It is the largest factor in how fast they use water. Moving them shadier costs nothing.
Relying on an untested watering system — Many release water much faster or slower than expected. Test before you leave, not after.

Questions people ask

How long can houseplants survive without water?

Most tolerate a week if watered thoroughly first and moved out of direct sun. Succulents manage far longer; thirsty plants in small pots much less.

Do self-watering spikes work?

They can, but release rates vary widely between products and with compost type. Test one for a couple of days before relying on it for a fortnight.