Cover story / 08.26

The useful
square metre.

A sunny patch the size of a café table can hold dinner herbs, a tomato, cut-and-come-again leaves, and enough flowers to keep bees visiting.

An old apartment balcony filled with practical potted plants — A small balcony is not a miniature garden. It has its own wind, heat, shade, and watering rhythm.

Several pots of leafy herbs in late afternoon sunlight — Kitchen herbs earn the closest spot to the door.

Late summer ledger

August 21–September 20

This month in the garden

Warm soil still gives quick results, but containers lose moisture fast. Work early, water deeply, and start the crops that prefer shortening days.

SowRadishRocketSpinach

Direct sow in a shallow drill; cover lightly and keep the surface damp until germination.

PlantParsleyChivesViolas

Set seedlings at the same depth they grew in the nursery pot. Water the root ball, not just the surrounding mix.

HarvestTomatoesBasilBeans

Pick little and often. Regular harvesting keeps beans flowering and stops basil stems becoming coarse.

WatchAphidsDry potsMildew

Check leaf undersides, test soil moisture with a finger, and give crowded leaves more air.

A metal watering can resting among green carrot tops — Water until it leaves the drainage holes. A quick splash only wets the top layer.

A red nasturtium flower among round blue-green leaves — Plate 05 · Garden nasturtium · edible leaf, flower, and seed pod

Plant portrait / No. 05

Nasturtium is happy to spill.

Give it a railing pot or the edge of a raised bed and let the stems find their own route. The leaves taste peppery, the flowers bring color to salads, and pollinators work through them for weeks.

Light: Full sun to partial shade
Water: When the top 3 cm feels dry
Container: 25 cm deep, free draining
Feed: Little; rich soil makes more leaf than flower
Sow: Direct after frost, 2 cm deep
Pick: Young leaves and newly opened flowers

Field note: blackfly often gather on the soft tips. Pinch off the worst cluster and rinse the rest with water.

A four-foot balcony

Four containers, four jobs.

Keep the layout simple enough to water in five minutes. Put the tallest crop where it will not shade everything else, and leave a clear route to every pot.

DoorWall / warmest edge

01Tomato
30 L

02Thyme
Chives
Parsley

03Rocket
Lettuce

04Nasturtium
Viola

0 120 cm

01 / Anchor
One compact cherry tomato in a 30-litre container. Tie it to a firm support before the fruit becomes heavy.
02 / Daily use
Put herbs nearest the kitchen. Keep mint in a separate pot because its roots quickly occupy shared compost.
03 / Repeat crop
Sow salad leaves in two short rows, three weeks apart. Cut above the growing point for another flush.
04 / Edge
Let nasturtium trail over the rail while violas cover bare potting mix and shade the surface.

Green and ripening tomatoes hanging on a garden vine — A compact tomato still needs a large root run and steady watering.

Technique note / Containers

Refresh tired potting mix.

Old mix is not automatically spent. If it drains freely and the previous plant was healthy, remove the old roots and rebuild its structure before planting again.

Gloved hands settling a young seedling into loose soil — Press only enough to steady the seedling. Compacted mix leaves too little air around new roots.

First

Tip the mix onto a sheet. Pull out thick roots, old labels, and any compacted clods. Discard it if it smells sour or held a diseased plant.

Then

For every three scoops of old mix, add one scoop of fresh potting mix and one scoop of screened compost. Add grit only for plants that need sharper drainage.

Last

Check every drainage hole before refilling. Leave 2–3 cm below the rim so the pot can hold a proper watering without washing soil over the edge.

Container index / Late-summer sowing

Six crops for the cooling edge of summer

Harvest times are approximate from sowing. Cool nights slow growth; a warm sheltered wall often speeds it up.

Plant	Light	Minimum pot	Water	First harvest
Radish	Full sun	15 cm deep	Even moisture	4–6 weeks
Rocket	Sun / part shade	15 cm deep	Do not let it dry out	4–5 weeks
Leaf lettuce	Morning sun	18 cm deep	Consistent moisture	5–7 weeks
Spinach	Sun / part shade	20 cm deep	Regular, gentle watering	6–8 weeks
Parsley	Sun / part shade	25 cm deep	Water when surface dries	10–12 weeks
Spring onion	Full sun	15 cm deep	Even moisture	8–10 weeks

Fresh green lettuce filling a raised garden bed — Leaf lettuce tolerates closer spacing when harvested young.

From the garden notebook

Three corrections to common advice

N. 17

Stop watering containers on a schedule

Weather, pot size, leaf growth, and wind change how quickly soil dries. Push a finger 3 cm into the mix. If it feels cool and damp, wait; if it feels dry, water slowly until excess runs out.

Fresh thyme growing in a small rustic ceramic pot — Small clay pots dry from the sides as well as the surface.

N. 18

Mint should probably stay in its own pot

Mint spreads by vigorous underground stems. In a shared container it threads through every root ball and becomes hard to remove. Give it a broad pot, partial shade in hot weather, and regular pruning.

N. 19

Let a few herb stems flower

Pinching basil and chives keeps leaves coming, but leaving one or two stems in bloom feeds hoverflies and bees. Cut the finished stem back before it spends energy on a full crop of seed.

Hands cutting fresh rosemary sprigs with small scissors — Harvest above a leafy joint; avoid cutting deep into old bare wood.

A compact balcony crowded with flowering geraniums and green leaves

End paper / Late summer

Leave room for one plant with no job.

Not every pot needs to feed the kitchen. A flower you watch from the window is useful in its own way.

Return to this month’s work