How to Grow Carrots from Seed
Family: Apiaceae
Binomial name: Daucus carota
Life Cycle: Biennial (but usually grown as an annual)
When to Sow Carrot Seeds
Carrots can be grown year-round in most climates. Avoid planting in extremely hot or cold weather which can affect germination and growth. Use the table below to identify the best time of year to sow carrots in your climate.
| JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cool | ||||||||||||
| Temperate | ||||||||||||
| Sub-Tropical | ||||||||||||
| Tropical | ||||||||||||
| Arid |
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Preparation
Carrot plants are best grown in full sun. Choose a location that will receive at least 6 hours of full sun each day.
Carrot plants need a loose, well drained soil enriched with organic matter. Prepare soil by weeding it thoroughly, digging it over to at least a spade’s depth to loosen the soil, and adding aged animal manure or compost. Organic matter can be dug into heavy soil to lighten it so roots can grow freely. Keep the area free of weeds until planting.
How to Sow Carrot Seeds
Carrot seeds do not require any treatment (eg soaking, stratification) before sowing.
Carrot seeds grow best when they are sown directly into the garden.
- Sow seeds directly in the garden 5mm deep and 3-8cm apart, with rows 25-30cm apart.
- Keep soil moist but never wet or dry.
- Seeds should germinate in around 14-21 days at a soil temperature of 10-30°C.
- Young seedlings will need protection from pests, pets and weather until they are established.
Tip: Carrot seeds are quite small. Handle them carefully to avoid them blowing away or being washed away. Mix seeds with sand or fine potting mix prior to sowing or use a seed dispenser, damp toothpick or tweezers to help space them evenly. Press lightly into the surface after sowing so that the seeds make good contact with the soil. Take extra care to make sure seeds and seedlings don’t dry out. Read more about sowing small seeds here.
How to Grow Carrot
Carrot plants may need watering during the growing season. Water when the soil is dry about 5cm below the surface (test this by scratching away a little soil with your finger). Water deeply in the early morning or late afternoon. Avoid watering the leaves of plants to avoid fungal diseases. Learn more about watering here.
Optional: To give plants room to grow, thin seedlings when they are large enough to handle. Pull out any weak or small seedlings so plants are spaced about 3-8cm apart.
If soil was well prepared no extra fertiliser should be necessary. Fertilising can result in excessive leaf growth at the expense of roots forming. In poor soil use a fertiliser low in nitrogen and high in phosphorus, such as blood and bone, applied at the recommended rate.
How to Harvest Carrots
Carrots should be ready to harvest in approximately 70-140 days.
Roots are ready to harvest when they are large enough to eat, and can be harvested as needed. Harvest individual roots by gently pulling at the base of the leaves, or use a garden fork to lift multiple roots from the soil. Shake off any excess soil and cut the foliage 1-2cm above the top of the root. Store carrots in a perforated plastic bag in the fridge. For longer term storage carrots can be frozen or pickled.
Common Problems when Growing Carrots
Like all plants, carrot is susceptible to some pests, diseases and other problems. Below is a list of the most common problems gardeners encounter when growing carrot plants:
Whitefly is a sap-sucking insect related to aphids. They are often found in large numbers on the underside of leaves and will swarm in clouds when disturbed. Plants may have yellowing leaves or may wilt, and growth will be slowed. Whitefly can be removed with a garden hose or sprayed with soap spray. Badly affected plants should be destroyed. Attracting beneficial insects that will prey on whitefly can be beneficial. Read more about managing whitefly here.
Carrot fly (Psila rosa) is a flying insect that lays its eggs in seedlings. When the larvae hatch they live in the soil and burrow into the roots to feed. Include companion plants in your garden or use insect exclusion netting over your crops to deter the pests.
Bolting is when a plant prematurely flowers and goes to seed. Bolting can be caused by a period of extreme weather. Avoid sowing seed until after the danger of frosts has passed or in very hot weather. Water plants regularly and deeply in hot weather to prevent them suffering heat stress.
Forked roots are usually caused by stony or heavy soil such as clay. The roots cannot grow freely in the soil or hit rocks or other obstacles and split into two. Cultivate the soil well before planting, dig in some coarse sand or compost to lighten the soil, or grow round or short varieties suited to heavy soil.
Split roots are usually caused by inconsistent watering when roots are mature. Water deeply and evenly to keep soil moisture consistent and always take recent or expected rainfall into consideration before watering.
Tough roots usually indicate that the roots were harvested too late. Harvest roots when they are young and tender.
Small roots can be the result of sowing too thickly or over fertilising. Thin seedlings to give roots adequate space to grow. Do not fertilise plants as this may encourage the growth of foliage at the expense of roots.
