Gadenin日本語Get the appPick from the top, never strip the bottom
The instinct is to take the big leaves at the base and leave the small ones at the top to grow. Do that with shiso and the plant runs straight up, because the growing tips are untouched and the lower leaves that were feeding the plant have gone. Harvest from the tips instead: take the top pair of leaves and the shoot they sit on, and you have picked and pinched in one action.
Start harvesting properly once the plant has eight to ten pairs of leaves, usually four to six weeks after planting out. Take no more than a third of the plant at a sitting. A shiso stripped to bare stems takes ten days to recover and gives you nothing in the meantime.
- Cut the top of a shoot Take three to four inches (8 to 10 cm) off the end of a shoot, cutting just above a joint. You get two or three usable pairs of leaves and the plant branches from the cut.
- Rotate around the plant Work round the bush rather than taking everything from the side nearest you. Even harvesting keeps the plant balanced and stops one side shading the other.
- Take yellowing lower leaves as you go Leaves at the base that have gone pale or yellow are no longer feeding the plant and hold moisture against the stem. Remove them, but do not take green ones from the bottom.
- Pick in the morning Leaves cut early, before the sun has been on them, are firm and hold their scent. The same leaf cut in the afternoon heat is already limp and wilts within the hour.
Pick every few days rather than in one big harvest a fortnight. Frequent light picking keeps the plant in vegetative growth and delays the moment it commits to flowering.
The leaves tell you what the plant is doing
Leaf size, color and thickness are a running report on the plant. Learn to read them and you can correct a problem two weeks before the harvest suffers for it.
| What you see | What it means | What to do |
|---|---|---|
| Large, thin, deeply scented | Growing well with enough water | Keep picking as normal |
| Small and thick, dark | Short of water, or the pot is too small | Water more often; pot on if roots are circling |
| Pale all over, large but weak | Too much nitrogen, or too little light | Stop feeding; move into more sun |
| Small, narrow, crowded at the tip | Flowering has started | Pinch out spikes two joints down |
| Tough with a faint scent | The plant is past its best | Harvest the whole plant and preserve it |
Keeping cut leaves fresh
Shiso wilts fast. A leaf that looks perfect on the plant can be limp fifteen minutes after cutting on a hot day, because the leaves are thin and lose water quickly through a large surface. The fix is to stop that water loss immediately rather than to revive the leaf later.
- Stand the stems in water Harvest whole shoots rather than loose leaves and stand them in an inch of water like cut flowers. They will hold for three or four days on a cool worktop out of direct sun.
- Wrap loose leaves damp Stack loose leaves flat, wrap them in damp kitchen paper and put the parcel in a bag in the fridge. Expect about a week. Stacked dry they go papery in two days.
- Do not wash until you use them Water sitting on the leaf surface causes dark, slimy patches within a day. Wash only what you are about to use.
- Keep them out of the coldest part Below 41F (5C) the leaves develop translucent brown patches from chilling. The fridge door or a salad drawer suits them better than the back of a cold shelf.
Dealing with a glut
A well-pinched plant produces more than a household can use fresh, and it all arrives at once. The preserving methods are not equal: the aromatic compounds that give shiso its scent are volatile, so anything involving prolonged heat or slow air-drying loses most of what you grew it for.
| Method | How well it works | Keeps for |
|---|---|---|
| Layered with salt | Very good; scent and color both hold | Six months in the fridge |
| Chopped and frozen in oil | Good; loses a little brightness | Six months in the freezer |
| Frozen whole in a bag | Fine for cooking, not for garnish | Three months |
| Air-dried in bunches | Poor; most of the scent goes | One year, but weak |
| Steeped in vinegar | Good, and red leaves color the vinegar deeply | A year in a cool cupboard |
Red-leaved shiso gives up a strong color in anything acidic, turning vinegar or a brine a clear crimson. Green-leaved shiso does not do this, so choose according to whether you want color or scent.
Flower spikes and seed heads are a crop too
When the plant finally goes over to flowering, there are two more harvests in it. Cut the spikes while the buds are still green and tightly closed and they carry the plant's scent in concentrated form. Left a little longer, the small green seeds along the spike can be stripped off between finger and thumb and used the same way.
Once the seeds harden and turn brown the eating season is over, and you have a different decision to make about whether to let them fall.
- Green spikes, buds closed Cut the whole spike with an inch of stem. Strongest scent of the three stages. Use within two days or freeze.
- Soft green seed Once the lower flowers have dropped and small soft seeds have set, run the spike through your fingers to strip them. Mild, with a texture to them.
- Hard brown seed Too hard to eat, but this is the stage to collect for sowing. Cut whole spikes into a paper bag and hang them somewhere dry for two weeks, then shake.
- Decide before it drops Any spike left on the plant past this stage will shed seed onto the soil. Cut and remove every spike you do not intend to sow yourself.
Record the date of your first cut and your last usable one each year, along with where each plant stood. After two seasons the pattern tells you when to start a second sowing so the picking never has a gap in the middle.