As with all vegetables, carrots grow best when they have the right amount of water and food. Even if you are growing carrots in the ground, they still need a constant supply of nutrients rich in potassium, air, and nitrogen. And when growing carrots in a pot or container with limited space, you need to take even more care that the soil is balanced and not sodden.
Soil Conditions
Because carrots grow underground, you need to prepare the soil to prevent any build-up of moisture that will cause rot. You also need to leave them alone until they are ready, so the soil should be full of the types of nutrients they thrive on.
Compact or Loose Soil
A carrot will grow in the direction of least resistance, and if it comes across hard soil or a rock, it will try to grow around it. For some, it does not matter, but if you want straight carrots, you will need to prepare the soil first. This means pulling out the rocks from the pot and mixing in fertilizer and large grain sand for drainage.
Nutrients
Carrots grow thicker, heavier, and longer in potassium- and phosphorous-rich soils. The nitrogen levels need to stay low; carrots develop more hairs in nitrogen-rich soil. Avoid animal manures, as these tend to have strong concentrations of nitrogen.
Note: If you must use compost or manure, dry it first.
pH Levels
The carrot relies on healthy bacteria and passive insects to aerate and balance the soil. All these organisms work together best when the pH is between 6.0 and 6.8. Below or above this, the carrot will grow slower, leaving it open to disease.
Above a pH of 7.0, try to bring the pH down by mixing peat or compost into the soil.
Below a pH of 6.0, increase the pH with wood ash or dolomitic lime.
Making Your Mix
Though it is still better to buy compost for carrots, fertilizer, and nutrients from a garden shop, you will still get better carrots if you make a blend.
Follow the ingredients below for making the best soil mix for carrots: –
25% Soil — this is regular topsoil from a garden.
25% Compost — Compost or manure, and make sure that it is dry and rotted through.
25% Sand — the best sands to use are perlite or vermiculite, which are pH neutral and are good at retaining water. Do not use beach sand, which will release a lot of salt into the soil.
25% Peat — you can use coco peat or moss; both are rich in nutrients and have natural anti-fungal properties.
Ready-Made Soil
If you lack access to a garden where you can dig out the soil, you can also buy pre-mixed soil that has everything your carrots need. When buying a soil mix, look for slow-release mixes. Slow mix soils help to balance the pH and keep the nutrients flowing during your carrot’s 12-week development.
You also want the soil to stay loose and prevent moisture build-up. Mixes holding sand or perlite improve drainage and aeration — and use a mix with as close to a neutral pH as possible.
Suitable products include:-
CUQOO Houseplant Potting Compost Mix — Perfect for growing vegetation in pots indoors. Available in 8-litre bags.
SA Products Multi-Purpose Compost — A versatile soil blend, ideal for carrots. Available in 60-litre bags.
Brian Sheridan has an allotment in Edgbaston and is a competitive grower. Brian is also a keen photographer and loves cooking. Brian and his wife Mary will also be running a stall at Edgebaston artisan market this year, selling products made from the allotment, including his award-winning relish!