Daniel Ashworth
Why a Small Herb Planter Earns Its Space
If your garden is a narrow courtyard, a rented flat's balcony or a patch of paving outside the back door, a full-scale raised bed is probably out of the question. A compact timber planter solves that neatly. Built to roughly 80cm long, 25cm wide and 25cm deep, it holds six to eight herb plants, sits comfortably under a kitchen window, and costs very little if you use reclaimed boards. Because you can reach it without bending, you will actually pick from it — and herbs that get picked regularly crop harder and taste better. Best of all, the whole build takes an afternoon with a saw, a drill and a screwdriver.
Sourcing Reclaimed Timber and Sorting Your Kit
Old scaffold boards, decking boards, pallet slats and shelving pulled from a skip all work beautifully. Look for sound timber around 2cm thick and at least 12cm wide, with no soft, crumbly patches or active woodworm. Give everything a scrub with a stiff brush and let it dry before you start.
One important caveat: avoid timber that has been treated with creosote or old-style heavy preservatives, and steer clear of reclaimed railway sleepers, as these can leach tar and oil into the compost. Modern tanalised timber is generally considered suitable for growing, but for herbs you will be eating, untreated or naturally durable wood is the simplest choice.
You will need:
- Two boards 80cm long, two boards 25cm long (or enough shorter boards to cut these)
- One base panel roughly 75cm by 20cm, or offcuts laid side by side
- Four corner battens about 4cm square and 25cm long
- Four offcuts for feet, roughly 5cm by 5cm by 10cm
- 40mm exterior wood screws, plus a few 25mm screws
- Horticultural grit, peat-free multipurpose compost
- A permeable membrane or weed fabric offcut
Tools: a saw, drill with 3mm pilot bit and 10mm bit, screwdriver, sandpaper or a sanding block, tape measure, pencil and a square.
Sanding, Cutting and Prepping the Boards
Measure twice and cut once — reclaimed timber is often slightly cupped or twisted, so cut the shorter pieces to fit the long ones rather than trusting your original measurements. Sand every sawn edge and any rough faces that will be visible, working down from a coarse grit to something finer. This takes ten minutes and saves snagged sleeves every time you water.
If you want a warmer tone, brush on a coat of oil-based wood stain or a natural linseed oil and leave it to dry for 24 hours before assembly. Avoid varnish, which cracks and traps water, and skip any treatment on the inside faces altogether.
Assembling the Box
Stand the two long boards on edge and position a short board at each end, forming a rectangle. Slide a corner batten into each inside corner and clamp or hold it steady. Drill pilot holes through the outside face into the batten and drive in 40mm screws — two per join, top and bottom, is ample.
Turn the frame over and fix the base panel to the underside, screwing up into the sides. If your base is made from narrower offcuts, leave 3-4mm gaps between them for drainage, or drill a row of 10mm holes every 15cm through a solid panel.
Next, screw the four feet to the underside of the base, one at each corner. These lift the planter clear of damp paving, which dramatically extends the life of the timber and stops the compost sitting in a puddle all winter. Finally, line the base and about 5cm up the sides with permeable membrane — it holds compost in while letting surplus water drain freely.
Compost and Which Herbs to Plant
Fill with a mix of roughly three parts peat-free multipurpose compost to one part horticultural grit. Mediterranean herbs loathe rich, soggy conditions, so lean towards more grit for those and a little less for parsley and chives.
- Basil — pinch out the growing tips to keep it bushy
- Flat-leaf parsley — slow to germinate but generous once established
- Chives — cut them right back and they will regrow within weeks
- Thyme, oregano and rosemary — happiest at the drier end of the planter
- Mint — plant it in its own pot sunk into the compost, or it will take over
Set taller herbs such as rosemary at the back so they do not shade the low growers, and leave 10-15cm between plants so air can move around them.
Looking After It Through the Seasons
A small volume of compost dries out and runs out of nutrients far faster than open ground, so check the moisture every couple of days in summer and water gently at the base rather than over the leaves. Feed leafy herbs fortnightly with a dilute liquid seaweed tonic; go easier on the woody Mediterranean types, which resent overfeeding.
Harvest little and often, taking no more than a third of any plant at once. In autumn, move the planter into a sheltered spot against a wall, trim back any straggly growth, and raise it onto its feet if it is not already clear of the ground. With a quick sand and a fresh coat of oil every couple of years, the same box will keep you in fresh herbs for a decade or more.
