Growing Ice Plant in Pots: Mix, Pot Size, Watering and Overwintering Under Cover

Why a pot is often the better choice

This is one of the few edible crops that is genuinely easier in a container than in the ground. Everything it wants, sharp drainage, lean soil, reflected heat, and a little salt in the root zone, is easy to arrange in a pot and awkward to arrange in a vegetable bed you also use for other things. In a pot you can move it into the sun, keep it dry in a wet spell, and throw the salty mix away in autumn.

The plant's habit suits pots too. It sprawls outwards rather than upwards, reaching perhaps eight inches (20 cm) tall and a foot and a half (45 cm) across, and it looks good spilling over the rim of a wide container. It needs no support of any kind and it does not blow over.

The one thing a pot changes for the worse is water. A small volume of gritty mix in full summer sun dries out fast, and while this plant tolerates dryness far better than most salads, a container that goes bone dry repeatedly gives you tough, bitter, flower-prone plants rather than tender shoots. Pot size is the way you buy yourself margin.

Depth is not what matters. This plant is shallow rooted and spreads sideways, so a wide low container gives more usable root volume per inch of depth than a deep narrow one.

The mix and how to fill the pot

Do not use a standard all-purpose potting mix on its own. It holds too much water, contains too much nitrogen for this crop, and produces exactly the soft dull plant you are trying to avoid. Cut it heavily with grit. Two parts of ordinary potting mix to one part coarse sand, fine gravel or perlite is a good working mix, and a purpose-made cactus and succulent compost with a little extra grit works straight from the bag.

Check the drainage hole before you fill. It needs a genuinely open hole, not a plastic tray permanently full of water underneath. Standing water at the base of the pot is the single most reliable way to kill this plant, and it kills it fast, from the crown down.

Fill to about an inch (2.5 cm) below the rim so there is room to water properly, and top the surface with a half inch (1 cm) of coarse grit. That top dressing keeps the sprawling stems off wet compost, reflects light up into the underside of the leaves, and stops the surface capping over.

1. Mix two parts compost to one part grit Combine in a bucket or on a sheet before filling so the grit is evenly distributed. A layer of grit at the bottom of the pot does nothing useful; it needs to be through the whole volume.
2. Check the drainage hole is open Cover it with a piece of broken pot or fine mesh to keep the mix in, then make sure the pot stands on feet or on gravel rather than flat in a saucer of water.
3. Plant at the same depth it was growing Set the plant so the crown sits at the surface, not buried. A crown planted low sits in damp mix and rots at the point where every stem joins.
4. Top dress with coarse grit Half an inch (1 cm) of grit or fine gravel over the surface. It keeps the sprawling stems dry underneath and makes a noticeable difference to how clean the leaves stay after rain.
5. Water it in and then leave it alone Give one thorough soak after planting, then do not water again until the top inch and a half (4 cm) is dry. New plantings are the stage where people most often overwater and lose the crown.

Watering and feeding a pot through the summer

The rhythm is soak and dry down. Water until it runs freely from the base, then leave the pot until the top inch and a half (4 cm) of mix is dry to a finger. In high summer on a sunny patio that may be daily; in mild cloudy weather it may be once a week. Go by the pot, not by the calendar, and lift the pot if you are unsure. The weight difference between a watered and a dry pot is unmistakable once you have felt it a few times.

Feed very little. A weak balanced liquid feed once a month is plenty, and in a fresh gritty mix in the first six weeks you need nothing at all. If the plant is pale and stalled with small leaves, feed it. If it is large, green, soft and dull, you have already fed it too much and the answer is to stop and pick harder.

The salt watering is much easier in a pot than in the ground, because the pot is a closed system you replace each season. Once every week or two, use lightly salted water instead of plain, roughly a teaspoon in a gallon (5 ml in 4 L). Do it onto already damp mix, and every third or fourth watering give a heavy plain soak that runs out of the base to flush any excess through.

A pot that has dried out completely repels water and the whole soak runs down the gap at the side. Stand it in a bucket of water for twenty minutes to rewet the mix properly, then go back to normal watering.

Autumn, winter and starting again

This is an annual and it has no frost tolerance whatsoever, so a pot outdoors ends with the first cold nights. It begins to suffer well before frost: nights below 40F (4C) with damp compost turn the crown soft and brown, and the plant goes from full to collapsed within days. That is the point to strip everything worth eating rather than hoping for a better week.

A pot does give you one option the open ground does not. Brought into a bright, cool, frost-free porch, greenhouse or conservatory before the cold arrives, and kept distinctly dry, a plant will carry on giving small pickings for some weeks longer. Keep it in the brightest place you have and water sparingly, because under cover in low light it stretches and the glitter fades. It is a bonus, not a way of keeping the plant for a second year.

At the end of the season, throw the mix away rather than reusing it, particularly if you have been watering with salt. Wash the pot, and start again with fresh gritty mix from seed in spring. That single habit avoids both salt accumulation and any carryover of the root problems that follow repeated growing in the same tired compost.

Before you tip the pot out, note what the pot did. Its size, where it stood, how often you watered it and whether the plant sparkled or went soft. Container growing is a set of small decisions you repeat every year, and those notes are what stops you making the same one twice.

1. Take a final harvest at the first cold nights When nights start dropping below 40F (4C), pick everything usable in one go. Leaves are still good at that point, and waiting for another warm spell usually costs you the entire plant.
2. Bring one pot under cover if you want longer Move a single pot into a bright frost-free space before the cold arrives and cut the watering right back. Expect softer, less glittering growth, and treat it as a few extra weeks rather than an overwintering plan.
3. Empty and wash the pot Discard the used mix, especially if it has had salted water, and scrub the container out. Reused salty compost is a poor start for anything, including next year's ice plant.
4. Write down the pot and the position Record the pot size, where it stood, roughly how often you watered and how good the sparkle was. Next spring that note tells you whether to go bigger, drier or sunnier without guessing.