Gadenin日本語Get the appThe pattern of trouble with this crop
For a salad crop this is remarkably trouble free. The salty, glassy leaf surface is unattractive to many of the pests that ruin lettuce and spinach, and slugs largely leave established plants alone. When something does go wrong it is nearly always a growing condition rather than an organism, and the two culprits are too much water and too little light.
That changes what you inspect. Look at the base of the plant where the sprawling stems meet the soil, and look at the color and texture of the newest growth. A brown soft patch at the crown and dull stretched shoots are the two early warnings, and both are fixable if you see them in the first week.
Cold is the third one and it is not a disease. This plant has no frost hardiness and takes damage from cold damp nights well above freezing. Learning to recognize chill damage stops you treating something that only the weather caused.
| Problem | First sign | Underlying cause |
|---|---|---|
| Crown and stem rot | Soft brown collapse where stems meet soil | Wet soil, poor drainage, organic mulch against stems |
| Leggy dull growth | Long thin pale stems, few bladder cells | Not enough light, too much nitrogen |
| Aphids | Clusters on the softest shoot tips | Soft sappy growth from over-feeding |
| Damping off in seedlings | Thread stems collapse at the surface | Sowing too thickly onto a permanently wet surface |
| Chill damage | Water-soaked translucent patches | Nights below 40F (4C) |
| Early flowering | Small pale flowers, leaves shrink | Drought stress, root restriction, or simple age |
Rot, the one that kills plants
This is the failure that takes a healthy plant to nothing in under a week. The stems sprawl along the ground, and where they rest on soil that stays wet they go soft and brown. From there the rot travels back to the crown, and once the crown has gone the whole plant collapses even though the shoot tips looked perfect two days earlier.
Every cause is environmental. Heavy soil that holds water, a pot standing in a saucer, organic mulch heaped against the stems, overhead watering that soaks the crowded center of the plant, or a wet cool spell landing on an already damp bed. Rich compost makes it much worse, because soft growth rots far more readily than firm lean growth.
The response is drainage and light, applied before the problem rather than after. Grit through the soil, a gravel top dressing under the sprawling stems, water at the base only, and never let a pot sit in standing water. If rot has already started, cut the affected stems right back to firm tissue and pull the mulch away from the crown. Sometimes the plant recovers from the remaining healthy shoots. Often it does not, which is why prevention is the whole game.
- Use grit, not organic mulch Top dress with coarse grit or fine gravel under the sprawling stems. Straw, bark or compost against the stems holds moisture exactly where you least want it and is the most common trigger for crown rot.
- Water at the base, in the morning Direct water at the soil, never over the plant, and do it early so any splashes dry within the hour. Overhead evening watering leaves the crowded center of the plant wet all night.
- Never let a pot stand in water Raise containers on feet or gravel and empty any saucer after rain. A pot sitting in an inch (2.5 cm) of water for two days is enough to lose a good plant.
- Cut back to firm tissue at the first sign Remove any soft brown stem back to clean growth and take the material off the bed. Then look hard at why that spot stayed wet, and fix the drainage rather than repeating the treatment.
In a wet climate, grow this crop in a pot under an overhang rather than in the open ground. Controlling how much rain the roots receive is far easier than trying to drain a bed that gets soaked every few days.
Soft, dull, leggy growth and the pests that follow it
A plant with long thin pale stems and large flat leaves that barely glitter is a plant grown too kindly. Shade and nitrogen are the two causes. Either on its own produces stretch; the two together produce a plant that looks like a limp green groundcover and tastes of nothing much.
That soft growth is also what attracts aphids. They colonise the softest shoot tips, and a well-grown lean plant in full sun rarely carries enough of them to matter, while an over-fed shaded one can be covered. The pest is the symptom. Squash or wash off what is there, then correct the feeding and the light, and the problem does not come back.
Correcting it takes a fortnight and is entirely worth doing. Move the plant into the strongest light you have, stop all feeding, cut the watering back to soak and dry down, and pinch the stretched tips out hard so the new growth comes from lower joints. The shoots that come next will be shorter, thicker and visibly beaded, and you will be able to see the difference between old and new growth on the same plant.
| Symptom | Likely cause | What to do |
|---|---|---|
| Long thin stems, wide gaps between leaves | Too little light | Move to full sun, pinch tips to force branching |
| Big soft green leaves with little sparkle | Too much nitrogen, too much water | Stop feeding, let it dry down between waterings |
| Aphid clusters on shoot tips | Soft sappy over-fed growth | Wash them off, then correct light and feeding |
| Bland watery taste | No salt, rich mix, constant moisture | Lightly salted water every week or two, leaner conditions |
| Leaves small and tough, flowers appearing | Drought stress or a root-bound pot | Water more consistently, pot on or resow |
| Seedlings toppling at soil level | Damping off from a wet crowded surface | Sow thinner, improve airflow, water from below |
Cold damage, and knowing when to stop
There is no frost hardiness here at all, and damage starts well before a frost. Nights below 40F (4C), especially with damp soil, mark the leaves with dark water-soaked patches that go translucent and then collapse. A genuine frost turns the whole plant to mush overnight. No row cover or cloche is worth the effort for a plant this tender at the end of an annual life.
Recognize the signal and act on it. When the nights start dropping and growth visibly stops, that is the point for a final large harvest rather than waiting for a warmer week. The leaves are still perfectly good at that stage, and waiting normally costs you the entire remaining crop.
Then clear up properly. Take the collapsed plant off the bed rather than leaving it to rot in place, because soft succulent material breaking down at soil level is an invitation to slugs and rot in whatever you plant there next. If you have been watering with salt in a bed rather than a pot, note where that bed was and choose something salt-tolerant to follow, or leave it a season to wash through.
Finally, write down what actually went wrong and where. Which plant rotted first and after what weather, whether the leaves were dull all season or only in one position, and the date the cold ended it. Those notes are worth more than any general troubleshooting list, because almost every problem with this crop is site-specific.
- Take the final harvest at the first cold nights When nights head below 40F (4C) and growth stops, strip everything usable in one session. There is no gradual decline to work with; the plant goes from good to lost in a single cold night.
- Clear the plant off the bed Pull the whole plant and take it away rather than digging it in. Wet succulent material rotting at soil level over winter feeds slugs and holds disease at the surface.
- Deal with salted ground before you replant If you salted a bed rather than a pot, do not plant a sensitive crop there next. Salt does not break down, and only rain or heavy irrigation moves it out of the root zone.
- Record what failed, where and when Note which plants rotted and after what weather, which positions gave dull leaves, and the date the cold finished the crop. Next year that tells you where to put it and how much rain it can be allowed to catch.