This page has the numbers for dill in the table above: spacing in and between rows, direct sown on your last frost date, and a week or three to germinate. What the numbers do not carry is the two things that actually decide how dill goes for you.
The first is that it will not transplant, so it has to be sown where it will grow. The second is that leaf, flower head and seed are three different harvests, weeks apart, and most advice treats them as one.
Dill companion plants
Dill is planted beside more vegetables than almost any other herb, and unusually for companion planting there is a real mechanism behind the main claim rather than folklore.
The mechanism is the flowers. Dill's flower head is an umbel — dozens of tiny, shallow, open flowers on a flat plate. That shape is accessible to small beneficial insects that cannot feed from deeper flowers: parasitic wasps, hoverflies, lacewings and tachinid flies. Those insects lay eggs in or near aphids and caterpillars, and their larvae do the work. Attracting beneficial insects is the best-supported of the companion planting mechanisms, and dill is one of the plants most often named for it.
Two consequences follow, and both are usually missed:
- The benefit comes from dill in flower, not dill as a leafy herb. A patch kept pinched back for kitchen use feeds nobody. If you want the pest control, let some plants flower.
- It is a garden-wide effect, not a next-door one. The wasps are not confined to the neighbouring plant, so dill anywhere near the vegetables works. It does not need to be interplanted in the same row.
Best neighbours. Cabbage and the rest of the brassicas gain the most, because cabbage worms and aphids are exactly what those wasps attack. Cucumbers, lettuce and onions are easy neighbours with no conflict in their requirements. Dill's own needs are undemanding — sun, and soil that is not rich — so it fits beside most things.
Keep it away from carrots. This is the one avoid-pairing worth taking seriously. Dill and carrot are in the same family, close enough that the two can cross if both are left to flower, which matters if you save carrot seed. They also share pests, so planting them together concentrates a problem rather than dividing it. Our carrot guide covers those pests.
Tomato is the traditional second avoid, on much weaker evidence. The claim is that mature dill inhibits tomato growth. It is repeated everywhere and tested almost nowhere. Does companion planting actually work goes through which of these claims hold up and which do not.
One practical caution that is not about companions at all: dill grows tall on hollow stems and blows over. Put it where it will not fall across a shorter crop, or where neighbouring plants hold each other up.
Sowing dill seed
Direct sow, always. Dill has a taproot that resents disturbance, and a moved plant either collapses or bolts straight to flower without making leaves. This is the single most common reason a garden-centre pot of dill fails in a bed, and it is why the quick facts table above shows no indoor sowing or transplanting dates, with the reason in each row instead.
Sow on your last frost date and then again every few weeks. Dill runs to flower quickly in warm weather, so a single sowing gives you a short leaf harvest and then a flowering plant. A short row every two or three weeks is what keeps leaves coming; the succession planting schedule covers that pattern across crops, and the planting date calculator will work the date out from your frost date.
Sow shallowly — the seed needs barely covering — and keep the surface damp until the seedlings appear. Thin to the spacing in the table above rather than leaving a dense stand, which produces weak plants that flop sooner. The plant spacing calculator turns that spacing into plant counts for a bed.
Dill will grow in a pot, but it needs depth for the taproot rather than width, and a tall plant in a light pot blows over. Sow a few seeds directly into the final pot rather than transplanting seedlings into it.
Soil, water and feeding
Poor to average soil suits dill. Rich ground and a nitrogen feed give tall, soft, leafy plants that flop and are more attractive to aphids.
Water is the one place a schedule genuinely does not help. Keep the seedbed damp through germination, because the seed is sown shallow and a dry afternoon can lose the row. After that, water in dry spells rather than at fixed intervals: a dry check is what triggers early bolting, and early bolting is what cuts the leaf harvest short. None of the publications behind this page puts a weekly figure on it, so the quick facts table says so rather than inventing one.
Harvesting dill: three harvests, not one
This is where dill differs from every soft herb, and where most advice collapses three things into one instruction. The plant gives you three distinct crops at three distinct times, and they trade off against each other.
Leaf
The first harvest, and the shortest window. Take leaves from young plants before any flower stem appears, because flowering changes both the amount of leaf and its flavour.
Pick whole outer leaves and side shoots with a short length of stem, working from the outside of the plant inwards, and leave the growing tip. Stripping individual leaflets off does more damage for less return. Cutting a whole young plant off a couple of inches above the soil will often give one more flush of growth.
Once a flower stem rises, the leaf harvest is effectively finished. Pinching that stem out as soon as you see it buys a week or two, but not a season — the plant is an annual and flowering is where it is going.
Dill loses its flavour quickly once cut, and more quickly again when dried. It freezes far better than it dries.
Flower head
The middle harvest, and the one pickling recipes are actually asking for when they say "dill heads". Cut the head when it is fully open and still green, before any seed has started to harden and colour. A green head carries the leafy, aromatic flavour; a dry one carries the sharper flavour of the seed.
Cut the head with a good length of stem — the stem is aromatic too and goes into the jar with it.
Seed
The last harvest. Leave heads on the plant and let them go from green to tan, and the seeds from soft and pale to hard and brown. The seed ripens unevenly across a head, so there is a judgement call: too early and the seed is soft and poor-flavoured, too late and the head shatters and sows your bed for you.
The standard method handles the unevenness. Cut the heads with a long stem once most of the seed has coloured, put them head-down in a paper bag, and hang the bag somewhere dry and airy. The seed finishes ripening and falls into the bag over a week or two, and nothing is lost to shattering. Rub the heads gently to release the rest, sieve out the debris, and dry the seed fully before storing it.
Seed saved this way sows next year's dill, which the plant will otherwise do for you.
Self-seeding, and what to do about it
Dill self-seeds enthusiastically. A single plant allowed to ripen and shatter its heads will give you dill in that bed the following year, and usually for years after.
Whether that is a feature or a problem depends entirely on the gardener. In an informal bed it is a free, self-renewing supply that comes up earlier than anything you sow deliberately. In a tidy rotation it is a weed that appears in the wrong bed and has a taproot that makes it annoying to pull once established.
Controlling it is simple: cut the flower heads before the seed hardens. Since the heads are worth harvesting green anyway, the pickling harvest and the seed control are the same job.
Seedlings that do come up are easiest to remove young, before the taproot goes down.
Common problems
It flowered almost immediately. Heat, a dry check, or root disturbance from transplanting. Sow again, direct, and keep the young plants watered.
It flopped over. Height plus wind plus hollow stems, made worse by rich soil. Grow it in a block where plants support each other, or somewhere sheltered, or give it a few canes and a loop of string.
Aphids on the stems. Common on soft, well-fed growth. The insects dill's own flowers attract are among the things that eat them, so tolerate a modest infestation rather than spraying — spraying kills the beneficials too.
It came up patchily. Shallow-sown seed in a surface that dried out. Water gently and daily through germination.
It never came up at all. Dill seed is short-lived. Seed kept for several years germinates badly; use fresh.
Our other herb guides are basil, parsley, lavender and rosemary, and the full set is on the crop guides index.