Gadenin日本語Get the appWhy roots fork
A carrot that splits into two, or that grows a mass of hairy side roots, does so because the tip of the taproot hit something and was damaged. Once the tip stops, side roots take over and thicken instead. It is not a disease, it is a physical accident underground.
There are three things it hits: stones and rubble, lumps of half-rotted compost or straw, and a hard layer you did not dig through. Add unrotted organic matter and the tip is scorched by the fertilizer and forks anyway. Nothing can be done after sowing, so soil preparation is the only control.
You can usually guess which of the three applies before you dig, from the state of your plot.
| Your plot | The root shape you get | What to do first |
|---|---|---|
| Stones and rubble in it | Split in two at the tip | Sieve the top twelve inches and take the stones out |
| Compost or straw from the last crop | A mass of hairy roots | Finish adding compost two months ahead |
| A hard layer underneath | Short and stopped, then thickened | Dig deeper, or build a taller bed |
| Shallow soil, or a container | The tip bends | Use a deeper container or a short rooted variety |
When you pull a forked root, dig down a foot in that spot and find out what caused it. Otherwise you repeat exactly the same shape next season.
Prepare the top twelve inches
A long rooted variety puts its root down six to eight inches (15 to 20 cm). Aim to have twelve inches (30 cm) of workable soil so the tip has room. Fine soil on top with a hard layer underneath means the tip stops exactly where the root should be filling out.
- Dig deep first Push a spade in vertically to a full spit and turn the soil over. The aim at this stage is to break the hard layer, so clods do not matter.
- Pick out stones and roots Work through the turned soil as though sieving it and remove any stone bigger than a thumbnail, old roots and bits of plastic. Assume one stone equals one forked carrot.
- Break the clods down Use the back of a hoe or a rake to reduce the top eight inches (20 cm) to an even crumb. On clay, choose a day when it is slightly dry and it breaks more easily.
- Build the bed and let it settle Make the bed and leave it a week to settle under rain. Sowing into freshly fluffed soil means it sinks afterwards and the roots bend.
If the bed will be sown in spring, dig it roughly in the coldest part of winter and let frost break the clods. It makes the spring work far easier.
Add compost and lime early
Unrotted compost is the one thing carrots will not tolerate. It carries on breaking down in the soil, and the root tip either hits a lump or is damaged by the gases and ammonia, and forks. If you use manure, use it well rotted and get it in at least three weeks before sowing.
Carrots dislike acid soil, so aim for pH 5.5 to 6.5. Do not apply lime and compost together: put the lime in a couple of weeks earlier. On a plot that gets limed for every crop, over-liming is the more likely problem.
| Material | Per square yard | When |
|---|---|---|
| Well-rotted compost | About 4 lb (2 kg) | At least three weeks before sowing |
| Lime | Only on acid soil | Two weeks before sowing |
| Base fertilizer | About 3 oz (100 g) | A week before sowing |
The same logic rules out digging in the last crop's straw or grass clippings just before sowing. If you want to use them, do it a whole crop earlier.
Keep the base dressing light and feed later
More base fertilizer does not give you bigger roots. Too much nitrogen early gives you leaf while the root lags, and a tip that meets a granule of fertilizer forks. Carrots bulk up in earnest around ten to eleven weeks from sowing, so design the feeding to support the second half.
- Spread it evenly over the whole bed Do not concentrate it in part of the bed. Scatter it across the surface before you dig and mix it in. A locally rich patch deforms every root that grows through it.
- Never directly under the seed A band of fertilizer under the drill is something the root tip will certainly meet. Mix it in evenly, or offset it between the rows.
- Split the feeding in two Feed after the second thinning and again after the last, scattered between the rows and worked in as you draw soil up. Feeding the second half is what fills the root.
If you get plenty of leaf and thin roots, cut the base dressing by a third next time. Overfeeding is a far more common carrot failure than underfeeding.
Bed shape and how many rows
On badly drained ground, build the bed up. Carrots rot in wet soil, and yet drying out too far triggers splitting, so what you want is a bed that drains but still holds moisture. Build it higher on clay and flatter on sand.
| Conditions | Bed width | Height | Rows |
|---|---|---|---|
| Average soil | 24 to 28 in (60 to 70 cm) | 4 to 6 in (10 to 15 cm) | Two, 8 in (20 cm) apart |
| Badly drained | 24 in (60 cm) | 8 to 10 in (20 to 25 cm) | Two |
| Sandy and dry | 28 in (70 cm) | 2 to 4 in (5 to 10 cm) | Two or three |
Keeping eight inches between rows makes it easy to place the later feeds and draw soil up. Any closer and there is no soil to draw.
Stony ground and containers
On ground where you cannot get the stones out, or a rented plot you cannot dig deeply, switch to a short rooted variety. Round and stump rooted types need much less depth and fork far less. You will harvest more that way than by insisting on a long variety and forking every root.
In containers the same rule applies. A pot at least twelve inches (30 cm) deep will grow a stump rooted variety, and a deep trough will grow a longer one. What matters is uniform, stone-free compost rather than the size of the pot.
- Choose by depth available Measure how deep you can genuinely work, subtract a couple of inches, and pick a variety whose root is shorter than that.
- Use bought compost in containers Garden soil brings stones and lumps with it. Bought vegetable compost sieved once gives the tip a clear run.
- Do not mix in fresh material Compost that is still breaking down does the same damage in a container as in the ground, and there is less soil to buffer it.