Carrots are one of the more challenging crops to grow successfully. Getting them to germinate and grow substantial roots could be difficult. However, I have significantly improved my yield with a few different tips and tricks.
Why Start Seeds?
Root crops like carrots, beets, turnips, etc. grow best when started from seed. Transplanting disturbs roots, leading to weird shapes and growth habits. Trust me, seeds are the way to grow. There are many more unique varieties, colors, and flavors available when starting anything from seed.
Planting Time
Carrots taste better after being exposed to cold weather. In the cold months, carrots convert starches into sugars as a defense mechanism against freezing temperatures. That is why I highly recommend starting carrots in the second half of summer in preparation for a late fall harvest.
Carrots will grow well as an early spring crop harvested in early summer, but they don’t taste great. Early summer carrots are often bitter and starchy. They’re great for soup and stock, but that’s about it.
Expect a longer days-to-maturity than is listed on the seed package if you want to grow substantial roots. Carrot seeds also take forever to germinate. For a Thanksgiving harvest, I started seeds (cold stratified) in late July here in New York Zone 7b. If started earlier in the summer, the carrots will suffer in the hot sun. If started later, the carrots won’t have enough time to grow plump roots.
Germination Trick: Cold Stratification
For two years now, I have been cold-stratifying carrot seeds. This shortens what would be a 2-3 week process into a 1-week process. All you need is a paper plate or plastic bowl (I’ve reused Chipotle entree bowls in the past), some seed starting mix, seeds, and a freezer. Here’s how:
- Fill a sturdy paper plate with seed starting mix.
- Generously sprinkle carrot seeds onto the starting mix, covering the plate. I often dump the whole seed packet.
- Place plates in ziplock bags. I recommend double bagging here to keep soil away from the food in your freezer.
- Place carrot seed ziplock bags in the freezer for 18-24 hours, no more and no less.
- Remove ziplock bags from the freezer and place them on a seed heat mat or on top of an appliance that releases heat. I set my heat mats to 75ºF/24ºC.
- After 4 or 5 days, you will see little white sprouts. Now, it is time to plant in its final planting location!
This simple process tricks the carrot seeds into thinking they’ve undergone a harsh winter. The 18-24 hour freezing is enough to speed germination without killing the seeds. The subsequent thawing and warming tell the seeds that it is time to grow.
Other Germination Method: Wooden Board Trick
If you don’t want dirt in your freezer, there is one other somewhat effective way to germinate carrot seeds. After loosening the soil, sow the seeds in the final planting place. Thoroughly mist the seeds with water and cover them with a wooden board.
Make sure the planting area under the board stays wet. The board protects the seeds from the harsh sun and helps the planting area stay moist. Carrot seeds need to be constantly wet in order to germinate. One dry day and the seeds will not sprout.
After about a week and a half, start checking for germination. As soon as the seeds sprout, remove the board so that the seeds can access light and begin to grow.
I’ve had limited success with this method, but it is more reliable than merely sowing seeds. I still highly recommend cold stratification.
Planting Location
There are some varieties, like Danvers 126, that perform fairly well regardless of soil type. However, large and uniform roots are more likely in loose, fluffy, and sandy soils. If your in-ground soil is very dense like mine, I recommend planting in containers or raised beds, where it is easier to create the ideal soil conditions. Planting in dense soil will often yield deceptively healthy carrot tops and twisted or forked roots.
I don’t have raised beds, so I plant in large containers. You want the containers to be at least one foot deep. Deeper containers will yield bigger roots.
Amend potting soil or raised bed mix with pearlite, vermiculite, and sand to create a well-draining, light, and fluffy growing medium.
How to Plant Cold-Stratified Seed Sprouts
The cold stratification process should result in little, white sprouts. It’s ok if you see some green leaves starting to form. Sprinkle the sprouts with the seed starting mix onto the growing area and cover them with a very thin layer of additional seed starting mix. Don’t worry about spacing. Keep the area moist and out of the harsh, afternoon sun until you see the first green leaves.
Thinning Carrots: Twice During Season
Thinning (removing) excess sprouts will ensure that roots grow to their fullest potential and don’t compete with each other for water and nutrients. Keep the healthiest, strongest-looking seedlings and remove the weaker ones. To thin, simply cut excess greens at the base about three weeks after germination when seedlings are about two inches tall. This will stop them from growing without disturbing the surrounding roots. Don’t throw out the leaves! Throw them into a salad, pesto, or your compost bin.
A second round of thinning is necessary about a month and a half into the growing season. Pull seedlings (removing the plant + roots) that are weak or too close to other seedlings.
Leave a space in between carrots equal to the diameter of mature carrots. In other words, leave at least 2-3″ of space around carrots in all directions. Follow the information about spacing and mature width listed on the seed packet.
Light and Temperature
Carrots require full sun to thrive. They grow best when temperatures are under 80ºF/27ºC. I recommend using 40-50% shade cloth when the carrots are starting to grow in the summer to protect them from extreme heat and strong sun. Shade cloth allows in enough light to grow and brings down the temperature. The carrots are more established and resilient come early fall, when I remove the shade cloth.
Watering and Fertilizing
Keep soil consistently moist. We can’t control the weather, but avoid large fluctuations in watering if at all possible. Excess water after a drought may lead to root rot.
Do not over-fertilize. Too much nitrogen-heavy fertilizer will create green top growth while leading to puny roots. I did not fertilize this year and had great results.
Harvesting and Storing
I like to wait until after the first couple of frosts and freezes before harvesting my carrots. You can guestimate the size of the carrots by gently scraping away the soil around the carrot tops.
After harvesting, trim carrot tops. Save carrot tops for pesto, soups/stocks, green mulch, or compost. Wash excess dirt off of the roots. Store roots in a plastic bag in the vegetable crisper for immediate use.
For more long-term storage, I’ve heard they store for months in wet sand. However, I haven’t tried this, myself. You could also cook and freeze them, but freezing would change the texture.
Varieties
Here are some varieties that I’ve grown successfully, in order according to taste and success in the garden:
Recap
- Planting Time: second half of summer OR late winter
- Cold Stratification
- Wooden Board Trick
- Where to Plant
- Thinning
- Light and Temperature Requirements
- Moisture and Fertilizer Requirements
- Harvest and Storage
- Trusted Varieties
