October 19, 2026

How to water plants while away from the garden

Soak every bed deeply the day before you leave, mulch the bare soil, and give whoever covers for you a way to see which bed has dried out. Water that soaks well below the surface sits out of reach of sun and wind, so it lasts days longer than a light sprinkle. The hard part comes mid-trip, when one bed dries out and its neighbors don't.

Beds in the same garden dry at different speeds. Raised bed 1 in our own garden held 39% to 54% moisture from mid-July through early September. Over those same weeks, readings in the ground bed ranged from 32% up to 62%. Its lowest reading came on August 6, the day after our hottest day of the year at 97°F. We don't know the full reason for the gap, because the crops, the soil depth, and the probe positions all differ. A timer would have given both beds the same water anyway.

Step 1. Soak each bed the day before you go

Water slowly until the soil is wet well below the top few inches. Slow water has time to soak in, so less of it runs off the surface. Morning works best, because cooler air and calmer wind lose less to evaporation. Our guide to the best time to water your garden covers the timing in more detail.

Step 2. Mulch the bare soil

Spread straw, shredded leaves, or finished compost over any exposed soil. Mulch shades the surface, and shaded soil stays cooler, so less water leaves through the top layer. Keep the mulch a little back from stems so they stay dry and don't rot.

Step 3. Put a probe in each bed and map it

A soil probe reads moisture at its own depth each time your station reports, and Siltwell checks those readings every 10 minutes. Open the station screen and assign each soil channel to the bed it sits in. Only a probe mapped to a bed can trigger a dry alert, and any member of the garden can do the mapping. Per-bed soil alerts need a connected station on a paid plan. The per-bed sensor setup guide walks through the hardware.

Push the probe into the root zone of the main crop, away from any dripper. If you have fewer probes than beds, put the first ones in the beds with the thirstiest plants.

Step 4. Invite the person covering for you

Garden sharing adds up to 3 members to your garden, and it sits on the same paid plan as soil alerts. Every member who keeps the soil-moisture notification on gets the push. Invites expire after 7 days, so send yours within a week of leaving and check that it was accepted. Ask your helper to open the garden once while you're still home, so you know their phone can see it.

Step 5. Check the rain guidance before anyone waters

The Today screen gives a garden-level watering answer for every garden, on any plan, as long as something is planted. It shows one of three states.

• Hold. The forecast for today and tomorrow shows at least 5 mm (about 0.2 in) of rain.
• Covered. At least 5 mm fell over the last 3 days.
• Water. No meaningful rain fell recently or is on the way.

This guidance reads the whole garden at once. It can save your helper a trip after a storm, but it cannot say which bed needs water.

Step 6. Water only the bed the alert names

A dry alert arrives as a push titled "Soil moisture low" and names the bed. It fires when the two most recent readings are both past the dry line, which is below 25% for a capacitive probe or above 60 cb for a tension sensor. Requiring two readings in a row keeps one odd reading from sending your neighbor out with a can. Each bed alerts at most once per day.

Suppose your tomato bed reads 24% at 2 p.m. and 23% ten minutes later. Your helper gets a push for that bed and waters it, and the other beds wait. Siltwell sends the alert and leaves the valve alone. It does not run a hose, so a person still has to carry the water.

None of our probed beds dropped below 32% between mid-July and early September, a stretch that overlapped a July with 10.89 in of rain. A dry alert would have stayed quiet the whole time, and nobody would have watered beds that didn't need it.

What can go wrong

• The probe sits in an unusual spot. A probe reports the soil right around it. Next to a dripper it reads wet while the far end of the bed dries.
• Seedlings dry before the probe does. Every bed uses the same 25% line, and you cannot set it per bed. Fresh sowings root in the top layer, which dries first, so ask your helper to check new seedlings by hand.
• Nobody sees the push. Soil alerts go out as push notifications only, with no email. If your helper turns off notifications, the alert never reaches them.
• A timer keeps running. A timer waters on schedule whatever the probes say, so a wet bed gets more. Our guide to garden watering systems covers what each type can sense.

A probe also cannot tell you how the plant is coping. On a very hot afternoon, leaves can lose water faster than roots replace it, so a plant can wilt while the probe still reads moist. That wilt usually eases by evening as the air cools and the leaves lose less.

Before you leave, mark each bed with a stake that matches its name in the app. An alert for raised bed 3 then leads your helper to the right soil on the first try.