Carrots can be one of the more challenging crops to grow in the home garden. The seeds are tiny, they can take 2-3 weeks to germinate, and you won’t be satisfied with the results if you don’t prepare the soil properly. But home-grown carrots are tastier and much sweeter than anything you’ll get at the store, so it’s worth it to learn how to grow carrots.
The carrots we’re familiar with today we’re most likely derived from the wild carrots of Iran and Afghanistan. Selective breeding over several centuries has given us a carrot that is sweeter, more colorful, and less woody than its wild ancestors.
Carrots are found in many shapes, sizes, and colors. They are divided into 6 main groups based on their shape:
- Small, Round – Orbit, Thumbelina
- Baby – Little Finger, Minicor, Short ‘n Sweet
- Chantenay - Red-cored Chantenay, Royal Chantenay
- Danvers – Denvers Half-Long, Danvers 126
- Nantes – Scarlet Nantes, Bolero, Nantes Coreless (I grow Nantes carrots exclusively! Nantes carrots are known for being sweet and consistent in shape and size, and there are more than 40 varieties of Nantes carrots to choose from.)
- Imperator – Avenger, Tendersweet
When to Plant
Spring – Carrots are cool season crops that should be planted around your average last frost date as long as the soil temperature is at least 60° F. Sandy soils will warm up more quickly in the spring than clay soils.
Fall – Determine your average first frost date and work backwards from there, plus 2 weeks. If your average first frost is October 15, and your seed packets says your carrots will mature in 70 days, count backwards 84 days (70 + 2 weeks) to get the planting date of July 23.
Start with relatively dry soil. If your soil is wet, wait until it dries out some. Begin by loosening the soil to a depth of 8-12 inches. This can be done by inserting a garden fork into a soil as deeply as possible, and then rocking it back and forth a few times. Move forward 6″ and repeat the process until the row has been loosened. If you find any sticks or rocks, be sure to remove them since any obstacle will cause a carrot to split
Carrots thrive in loose, well-drained soil, so reserve the areas of your garden with the best soil for carrots. Raised beds are ideal. Carrots grown in heavy soils will not be able to develop fully, and carrots grown in rocky soils will have defects such as splits and forks.
The pH of the soil should be around 6.5, which fortunately is a good pH level for most garden vegetables. So hopefully your soil is already in this range. If your pH is less than 6.5 (acid soil) add lime, ground limestone or dolomite to raise the soil pH. If your pH is high (alkaline soil) add pulverized sulfur rock to lower the pH. Note: Each pH unit represents a tenfold difference. So a soil with a pH of 5.0 is 10 times more acidic than a soil with a pH of 6.0. A soil with a pH of 4.5 is 100 times more acidic than a soil with a pH of 6.5. So don’t try to swing your pH levels too much at once!
Just prior to planting, broadcast an organic fertilizer that contains little nitrogen and more potassium and phosphate. The fertilizer bag will tell you how much nitrogen, phosphate, and potassium is contained in the fertilizer. For example, a 3-4-4 fertilizer contains 3% nitrogen, 4% phosphate, and 4% potassium. Too much nitrogen will cause the carrot to produce more foliage, while phosphate and potassium encourage better root development. Since carrots are root crops, phosphate and potassium are more important for good carrot growth.
Once you have the seed bed well prepared, make 1/2″ deep furrows in the soil spaced 12-18″ apart. (The edge of a scrap piece of 1″x4″ lumber works well for making these shallow furrows in the well-prepared soil.) Carrot seeds are EXTREMELY tiny, and it is difficult to control how many you’re planting, but try your hardest to plant no more than 2 seeds per inch. Carrots seeds are also very light weight, so don’t try to plant them on a windy day. There are now pelleted carrot seeds available that make planting much easier, but they are a little more expensive than regular carrot seed.
Carrots are known for being slow to germinate. It can take up to 2 weeks for the first seedlings to emerge, and the soil must be kept moist during this time. The soil surface must not be allowed to crust over or get compacted before the seeds have a chance to germinate. A great tip is to plant a few radish seeds with the carrots. The radishes will germinate very quickly and break through the soil surface. The radishes will also help mark the row. The radishes will be harvested in about 30 days after planting – by then the carrots will be a couple of inches tall and able to make it on their own.
Another tip – instead of using radishes, cover the rows with clear polyethylene file. This will help keep the soil warm and moist while the carrot seeds are germinating. Remove the poly film once the seedlings begin to appear.
Small carrot seedlings are very weak and don’t compete with weeds well. It’s important that you keep weeds under control for the first month. Pull weeds while they’re still tiny and before they have a chance to get established. Don’t do any deep cultivation because you’ll damage the roots of the seedlings. Damaged roots = damaged carrots.
Care while Growing
Once the carrot seedlings get about 6″ tall, come in with a pair of scissors and thin them to about 3″ apart. Don’t crowd them any closer than that, or you’ll end up with spindly carrots.
You can mulch lightly between the rows of carrots with a light covering of straw or dry grass clippings. This will keep weeds down, keep the moisture levels more consistent, and will keep the tops of the carrots from turning green, a condition called “green shoulders”. (If you have some carrots with “green shoulders” at harvest time, just cut off the green part – it’ll taste bitter).
There are a host of potential carrots pests: aphids, flies and maggots, wireworms, nematodes, and more. However, most of them can be kept under control using the same methods:
- If you have problems with these pests, be sure to remove all carrots and carrot debris from the garden each fall.
- If you’ve had serious problems for several years in a row, skip growing carrots for one year. This will break the pests life cycle, and next year you’ll have fewer problems with them.
- Turn the soil over in late winter. This will expose any hibernating larvae to frost and kill them.
- Rotate your crops each year. Try to use a 3 year rotation, so that you don’t plant carrots in the same place for at least 3 years.
There are also some common carrot diseases. Fortunately the same measures used to prevent pest problems will also help prevent disease issues.
Carrots can be harvested when the roots are around 1/2″ in diameter. With many varieties, the tops are not strong enough to withstand being pulled from the ground. You’ll need to dig next to the carrots enough to loosen the soil so that you can pull the carrots out of the ground. Carrots don’t need to be harvested all at once. You can harvest them as needed over a 3-4 week period.
Some gardeners keep their carrots in the ground until the first frost because it is said a frost makes them sweeter. Some even place a heavy straw mulch over the carrots and store them in the ground all winter long, but I had issues with mice when I tried this.
To store carrots, leave one inch of the green top – cut off the rest. Store in the refrigerator and keep the humidity high. Carrots can also be stored in a cellar in a bucket filled with moist sand. Carrots can easily last 4 months under cool, moist conditions.
Photo By Thamizhpparithi Maari (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons