Why do my hanging baskets need watering twice a day?

This is not the same problem as a pot drying out, even though it looks like it. A pot at least stands on something, is shaded on one side, and has some mass to buffer temperature. A basket is a small volume of compost suspended in moving air with sun on it from every angle, and physics is doing most of the work.

What you'll need

• A larger basket
• A solid liner
• Loam-based compost
• Long-reach watering lance (optional)
• Drip line and timer (optional)

Step by step

1. Accept which fixes are real.Volume, liner, compost and position. Those four are the levers. Watering technique, gels and clever routines are all marginal by comparison.
2. Go up a basket size.Volume rises steeply with diameter. A 400mm basket holds roughly twice the compost of a 300mm one and takes roughly twice as long to dry. This is the biggest single change available.
3. Replace an open liner with a solid one.A moss or open coir liner evaporates from its entire surface. A solid plastic liner, or a plastic circle inside a decorative liner, cuts that dramatically.
4. Put a third of loam in the compost.Loam-based John Innes holds far more water than a peat-free multipurpose, releases it more evenly and rewets readily if the basket does dry. It also adds useful weight.
5. Move it out of the wind.Wind removes more water from a basket than sun does. A basket on an exposed corner or above a windy passage dries several times faster than the same basket against a sheltered wall.
6. Hang it lower if you can.Air moves faster higher up, and a basket at head height is also much more likely to actually get watered. Both effects run the same way.
7. Mulch the surface.A layer of gravel, bark or even moss on the compost surface reduces evaporation and stops the surface capping.
8. Water properly when you do.Until it runs from the base, not a splash. A basket wetted only at the top has a dry core within hours, and a dry core repels water thereafter.
9. Rescue a basket that has dried out completely.Take it down and stand it in a bowl or bath of water for twenty to thirty minutes so it takes water up from below. Watering from above will not rewet compost that has gone water-repellent.
10. Fit a drip line if you have more than two or three.A 4mm micro-tube to each basket from a supply pipe, with a battery timer at the tap, running early morning. It is inexpensive and it removes the whole problem, including while you are away.
11. Consider a self-watering basket.Baskets with an integral reservoir genuinely extend the interval, typically from twice a day to once a day in high summer. They are not a substitute for adequate volume.
12. Check whether it is simply full of roots.By August a dense basket is mostly root and very little compost, so its reservoir has shrunk even though nothing has changed on the outside. That is normal, and it is why late summer watering is so relentless.

Tips

• Wind, not sun, is usually the biggest single factor. Shelter is worth more than shade.
• Water running straight out of the base means the compost is dry, not full.
• A watering lance with a long spout means the basket gets watered properly rather than optimistically from below.

Common mistakes

• Trying to solve it with more frequent light watering — A splash wets the top and evaporates. It also encourages the roots to stay at the surface, which makes the basket even more vulnerable.
• Choosing an open moss liner for a hot windy position — It evaporates from the entire outer surface. It looks lovely and it is the thirstiest option there is.
• Hanging a basket in the windiest, sunniest corner because that is where the bracket is — Position is a real variable. Moving the bracket is cheaper than the summer's watering.

If it doesn't work

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