How to Grow Carrot
'Autumn King 2' from Seed
Britain's finest maincrop storage carrot — a British heirloom with the RHS Award of Garden Merit, producing magnificent long roots of up to 30cm in deep orange with exceptional flavour, that can be left in the ground over winter or stored in sand for months
'Autumn King 2' is the carrot for serious kitchen gardeners — the maincrop, long-rooted, outstanding-flavoured variety that has won competitions at horticultural shows for decades and that genuinely earns storage space through the winter. The roots are impressive by any standard: cylindrical, tapering slightly at the tip, up to 30cm long, and a deep, rich orange throughout with a dense interior that roasts magnificently, keeps its colour when cooked, and has the full-flavoured sweetness that distinguishes a home-grown carrot from anything the supermarket supplies. The 'Autumn King' name describes exactly what this variety does — it is sown in spring, harvested in autumn, and it reigns through winter, either left in the ground as a living larder or lifted and stored in boxes of sand for months of continued use.
The RHS Award of Garden Merit — awarded in 1995 and maintained since — recognises Autumn King 2's consistently outstanding garden performance across a range of UK conditions and gardens. It is a British heirloom, developed and refined over generations of British growing, and the '2' in the name indicates it is an improved selection of the original 'Autumn King' — better germination, more uniform roots, greater resistance to splitting. If you grow only one carrot variety, Autumn King 2 is the one that most rewarding kitchen gardeners would choose.
Quick Facts at a Glance
Crop Type
Maincrop Carrot — British Heirloom
Sowing Time
April – June direct outdoors
Harvest
August – December (store into spring)
Award
RHS Award of Garden Merit ✓ (1995)
Root length
Up to 30cm — long cylindrical maincrop
Difficulty Rating
3 out of 5 — Carrot root fly management is the key challenge
Understanding the Variety
'Autumn King 2' is Daucus carota in the Autumn King group — a traditional British open-pollinated maincrop carrot type selected for maximum root length, storage quality, and flavour. As a maincrop variety it takes longer to develop than early varieties (approximately 12–16 weeks from sowing to harvest compared with 8–10 weeks for early types), but the resulting roots are significantly larger, more flavoursome, and far better for storage. The cylindrical roots with their blunt, slightly rounded tip (stump-rooted) are easier to grow successfully in heavier soils than the very sharply tapering forms of some varieties, though stone-free, deep soil still gives the best results.
The Winter Storage Advantage
Autumn King 2's greatest practical quality is its exceptional storage. After the autumn harvest, roots can be left in the ground through most UK winters — covered with a thick layer of straw or fleece to protect from hard frosts — and lifted as needed. Alternatively, the roots can be lifted in October or November, the tops twisted off, and the roots packed into boxes of damp sand or barely moist compost in a cool, frost-free location such as a garage or shed. Stored this way, Autumn King 2 roots remain in excellent eating condition for three to four months — providing home-grown carrot through December, January and February from the previous summer's sowing.
⚠️ Carrot Root Fly — The Primary Threat
Carrot root fly (Psila rosae) is the major pest risk for all carrot varieties. The flies lay eggs at the base of carrot foliage, attracted primarily by the volatile compounds released when the foliage is damaged (by thinning, weeding, or simply brushing past). The larvae burrow into the developing root, causing rusty brown channels that ruin both the appearance and the storage quality of the roots. Management: cover with fine insect-proof mesh from sowing to harvest; sow between late May and June to avoid the main spring egg-laying period; thin extremely carefully without crushing foliage; remove all thinnings from the site immediately. These measures combined give very effective protection without any need for chemical treatment.
Sowing & Establishment
Carrots are direct sown — the taproot development begins immediately at germination and transplanting produces forked, deformed roots without exception. All carrot growing begins with preparing the best possible soil: deep, loose, stone-free. This preparation is the most critical step in the entire process.
The Most Important Thinning Rule
When thinning carrot seedlings, never crush or bruise the foliage — the volatile compounds released by damaged carrot leaves attract carrot root fly from significant distances. Thin in the evening (when flies are less active), water the row beforehand to loosen the soil, remove plants by pulling straight up cleanly without disturbing neighbours, and immediately remove all thinnings from the site. Do not compost them on-site — remove them entirely from the area. Crush a few plants inadvertently and you may find your crop significantly damaged within a fortnight.
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Prepare the bed meticulously — remove all stones to 30cm depth. Stones cause forking — the root attempts to grow around the obstruction and divides. For 30cm Autumn King 2 roots, the entire depth must be stone-free. On very stony or heavy clay soil, grow in a raised bed filled with sieved topsoil and sharp sand, or use a deep container. Do not add fresh manure within 12 months of sowing — this causes forking.
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Install carrot root fly mesh before sowing. Put the mesh frame in place over the prepared bed before the first sowing. This eliminates the need to disturb the plants once sown. Use fine insect-proof mesh (mesh size ≤0.8mm) on supports at least 45cm high — the fly is a low flyer and a barrier of this height is very effective.
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Sow direct from April to June, 1cm deep in rows 30cm apart. Sow thinly in shallow drills — carrot seed is small and fiddly; mix with fine sand to help spread evenly if desired. Cover and firm. Keep moist until germination, which takes 10–21 days depending on soil temperature (warmer soil = faster germination).
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Thin to 5–8cm spacing with maximum care for foliage. Thin in the evening, after light watering, removing the smallest plants without disturbing their neighbours. Remove thinnings from the site immediately — they attract carrot fly. For very large roots, thin to 8cm; for a higher yield of medium roots, 5cm.
Growing On & Care
Careful Watering
Avoid overwatering once established — excess water encourages lush foliage at the expense of root development. Water deeply but infrequently: a good deep watering every seven to ten days in dry conditions, rather than light daily watering. Consistent but not excessive moisture produces the best roots. In wet summers, reduce watering entirely.
No Feeding Needed
Autumn King 2 needs no additional fertiliser once sown in previously composted or fertile soil. Feeding with high-nitrogen products promotes excessive leaf growth and reduces root sugar accumulation. If the bed was composted the previous autumn, no further feeding is required throughout the growing season.
Green Shoulders
When carrot tops protrude from the soil, the exposed top of the root turns green and becomes bitter — the result of chlorophyll developing in response to light exposure. Earth up the soil around the crown to keep the shoulder buried, or draw a little soil over the shoulder as the root develops. Regular inspection from August onwards prevents this easily avoided quality problem.
Leave in Ground Over Winter
Autumn King 2 can remain in the ground through UK winters with frost protection — cover with a thick layer of straw or fleece before the first hard frosts and lift as needed. The root actually sweetens slightly in cold ground, developing higher sugar content as the cold triggers starch-to-sugar conversion. Lifted roots in January from ground-stored Autumn King 2 are often the sweetest of the year.
Sand Box Storage
For bulk storage, lift roots in October or November before severe frosts. Twist off (not cut) the tops to prevent regrowth in storage. Pack roots in layers in wooden boxes or cardboard with slightly damp sand or barely moist compost between layers. Store in a cool, frost-free shed or garage. Check monthly and remove any that show rot. Well-stored Autumn King 2 keeps for three to four months.
Show Quality Roots
Autumn King 2 is specifically noted for producing exhibition-quality roots — long, uniform, deeply coloured, and visually impressive. To grow show-quality specimens, thin to 8–10cm spacing, grow in very deep stone-free soil prepared to at least 45cm, maintain consistent moisture, and harvest at peak maturity in October. The RHS AGM variety has won countless horticultural shows and remains the standard for long-rooted maincrop exhibition carrots.
Harvesting & Cooking
Getting the Best from Autumn King 2
When to harvest: From August as baby carrots (pull a test root to check shoulder width — 1–2cm is baby carrot stage), through to October for full-sized maincrop at 3–4cm shoulder width. For storage, harvest before the first hard frosts. For in-ground over-wintering, leave until needed, protecting with straw or fleece.
How to lift: Push a fork in alongside the root (not underneath — this damages the tip) and lever gently as you pull the top. In dry soil, water the row the day before lifting to soften the ground and reduce the risk of snapping the long roots. Autumn King 2's length means it takes more care to extract than short-rooted varieties — patience pays.
Roasting: The finest way to eat Autumn King 2. Cut into batons or leave whole (small roots). Toss with olive oil, honey, cumin, salt and black pepper. Roast at 200°C for 30–40 minutes until tender and caramelised. The natural sweetness of a late-season Autumn King 2 root is extraordinary when roasted — entirely different from the diluted, woody quality of a supermarket bag.
Slow-cooked dishes: Autumn King 2's large size and dense flesh makes it ideal for slow braises, stews and soups where it maintains its structure through long cooking rather than disintegrating. The root retains its orange colour well through cooking — a rich, stew-depth colour rather than the pale, washed-out tone of some varieties.
Raw: Julienned or grated, Autumn King 2 raw is sweet, crisp and deeply flavoured. The high beta-carotene content gives it a rich orange colour that makes it visually striking in salads and slaws. Grate coarsely and dress with orange juice, olive oil, and a little honey for a classic Moroccan-style salad.
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Common Problems & Solutions
| Problem | Likely Cause | What to Do |
|---|---|---|
| Rusty brown channels in roots | Carrot root fly larvae | Install fine insect-proof mesh before sowing — the most effective preventive. If damage is found, harvest immediately and use the undamaged portions. In subsequent seasons, use mesh from day one and avoid sowing before late May when spring fly pressure is lower. Remove and bury all thinnings. |
| Forked or multi-tipped roots | Stones; fresh manure; compacted soil | Remove all stones to 30cm depth before sowing. Do not add fresh manure within 12 months. Break up any compaction. On very stony clay soil, grow in deep containers or raised beds with sieved topsoil and sharp sand. The longer the root required, the deeper and more stone-free the soil must be. |
| Poor germination | Dry soil; cold soil; seed not in contact | Water the drill before sowing and after covering. Keep soil moist until seedlings emerge — this is when carrot seed is most vulnerable to drying out. Germination below 7°C is very slow; wait until soil has warmed in late April. Firm the soil over seed rows gently to ensure seed-soil contact. |
| Green shoulders | Root top exposed to light | Earth up the soil around the crown as roots develop from August onwards. A monthly inspection and gentle soil-drawing-up around the shoulder prevents the chlorophyll development that causes bitterness. This is easily prevented and almost impossible to remedy once it has occurred. |
| Splitting roots | Irregular watering after drought; very heavy rain | Water consistently in dry periods. Autumn King 2 is noted for good resistance to splitting — one of the AGM-winning qualities — but extreme drought followed by heavy rain can still cause it. Consistent, deep watering every seven to ten days in dry weather prevents the rapid uptake that causes splitting. |
Plant Specifications
The maincrop storage carrot that stands apart from everything in a supermarket
Autumn King 2 is the carrot that serious kitchen gardeners grow — not because it is easy (it requires proper soil preparation and vigilant carrot fly management) but because the reward is so clearly, obviously, inescapably superior to anything available commercially. Roots up to 30cm long, deeply orange, profoundly sweet, roasted to caramelised perfection or stored through winter in a box of sand — this is what the kitchen garden is for. Prepare the soil carefully, install the mesh, thin in the evening without crushing the foliage, and harvest in autumn one of the finest vegetables the British kitchen garden produces.
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