By growing carrots indoors, you simplify the entire growth process, customize the climate, and increase your degree of control over the final product. Still, there are a few things you should know before you start growing carrots inside your home.
You can start carrots indoors through one of several germination methods. You can then transplant them to an outdoor garden or container. You can also grow mature carrots indoors if you give the plants enough space to grow.
In this article, I will break down four germination methods. I will also tell you how to start seeds in various containers, whether you’re transplanting them or growing them inside.
Indoor Germination Methods
Carrot seeds take 14–21 days to germinate. If you plan to transplant the sprouted seeds or shoots, use this list to determine how long you have to wait for each method.
If you’re wondering whether you even need seeds to grow carrots, the short answer is that you do. If you’re curious, check out my article on whether you can grow carrots from carrot tops: Can You Grow Carrots From Just Carrot Tops?
Start Seeds in Soil Blocks
Soil blocks give seeds a huge advantage when you transplant them. You can make a soil block by shaping a water and soil mixture into a block. You then plant the carrot seeds according to the requirements displayed on the seed bag.
Soil blocks avoid container restraints by eliminating root circling. Since the roots check themselves when contacting air, they don’t require pruning and don’t become root bound.
When roots circle a container, they aren’t taking in proportional nutrients and may not be strong to survive the transplant.
With soil blocking, the young roots don’t grow beyond the block’s edges. After the transplant, the roots grow into the new soil from the proper development point, giving them the freedom to find the paths of least resistance.
Using soil blocks, you will have to pay closer attention to germination and estimated root growth. The roots should grow free from pressure and will therefore require transplanting before contacting the soil block bottom.
For a complete guide on how to DIY soil blocks yourself, watch this video by Utah State University Yard And Garden Extension:
Start Seeds in Resealable Silicone Bags
Starting seeds in resealable bags ensures they can germinate in ideal conditions, free from nature’s tampering.
Silicone resealable bags have begun replacing their plastic counterparts because you can reuse them thousands of times (or in some cases indefinitely), wash them in the dishwasher, and subject them to extreme temperatures. Their durability and longevity make them the perfect seed starting bags.
Here’s how to start carrots in a bag:
1. Choose a Size Depending on Carrot Variety
Select a variety suited for your container unless you plan to transplant early. Transplanting while shoots are young makes the transfer smoother, maximizing the plant’s chances for success. It also makes the process easier since you won’t have to worry about damage to developing roots.
2. Fill the Bag With Soil and Compost
Starting with a mixture of soil and compost, fill the bag four-fifths of the way. Consult the seed packet or variety-specific growing guide to determine how many seeds to sow, how deep to sow them, and their growth rates. Put the seeds on top of the soil and cover them with a very light layer of topsoil.
3. Water Carefully
Water slowly and carefully to avoid washing the seeds around. If watering displaces the seeds from the center of the bag, the roots may not have enough room to grow—the side of the bag or another root bundle can offset its natural path. Center placement allows the roots to radiate outward with as much space as possible between the center and the edge of the bag.
4. Thin the Shoots
Once shoots are around 4 inches (10 cm) tall, you will need to thin them. Check the seed packet or variety-specific growing guide for details on thinning requirements. In general, shoots need ¾ inch (2 cm) or so between each other.
When thinning carrots, you’re playing a direct role in selecting the best characteristics at the early stages. Thin according to space and how robust and healthy the shoots look.
You’ll get to know the varieties better, giving yourself data for future selections.
Start Seeds in Trays
If you plan to use this method, you may want to look for recyclable trays or biodegradable trays. Many plastic trays contribute heavily to the waste cycle, and good options exist for reusable trays.
An advantage of using a tray to germinate is using one with a plastic dome to retain humidity and encourage quicker germination. Trays have the same root ball preservation advantage as soil blocks, albeit with leftover materials to store in the trays.
Fill the trays with soil, leaving a little space at the top of each square, and pack to a light firmness. Push two seeds into a hole at the top of the soil, about ¼ inch (0.63 cm) deep. Water with as little pressure and flow as possible to avoid disturbing seed placement. Seeds and roots need plenty of room to grow into the soil with as little impedance as possible.
Start Seeds in Containers
Starting seeds in single containers allows you to sow a few in one small container or several at once (even different varieties together) in larger containers. You can have as many or as few as your desire and space allow.
Fill the container with soil and pack to a light firmness. Push the seeds into the top of the soil about ¼ inch (0.63 cm) deep and sprinkle small amounts of dirt over the holes. Water with minimal pressure and flow until the soil is moist at 1 inch (2.5 cm) deep. Stick your finger into the soil and make sure it’s wet all the way through.
Mind the light requirements for the varieties and number of seeds you sow in containers. They’ll need to bask in full sun, which means 6-10 hours per day. Use sunny windows, south-facing or close enough.
Don’t overcrowd containers—the foliage can block sunlight access for neighboring plants.
Container Types for Growing Carrots
Suppose you start carrots indoors and maintain the carrot plants in a container, allowing them to grow to full size. In that case, you’ll need to choose the right container based on the variety of carrot seeds you’re planting and your available growing space.
By consulting the seed packet or guide, find the growth expectations for the variety you’re planting. Each carrot plant should have room to spread its foliage, though once they develop, you can bind the stems and leaves until harvest.
Hard-Sided Pots
Solid-walled or hard-sided growing pots, such as traditional flower pots, stabilize the immediate area surrounding the plant and roots, allowing the plant to grow free from wind or animal interference. Smaller pots work well for growing indoors because you can maneuver them to any location.
Pots work well for growing carrots, but before planting, you must determine the space you’ll need for a mature carrot taproot, plus space underneath for soil and drainage.
If you don’t plan for drainage and decide to water specific amounts instead, make sure you don’t saturate the soil or leave your carrots in wet soil. This will cause them to rot or split. You can still eat split carrots, but if you see them splitting, you should adjust your watering schedule to reduce hydration.
Grow Bags
You can grow carrots indoors using grow bags instead of soil blocks or traditional hard-sided containers. You have two main options for bag materials in the grow bag world: plastic and fabric.
Plastic Bags
Plastic bags come in a huge variety of shapes and sizes. Commercial plastic bags made for gardening often have drain holes, but not always. Smaller bags work very well in limited growing spaces.
If the plastic does not biodegrade or compost, you must transplant the young shoots and surrounding dirt from the bags into prepared soil. Take extra caution here—plastic bags can shift, and you don’t want to disturb the transplant.
Fabric Bags
Fabric grow bags made from natural materials are biodegradable, which means they compost well and allow you to plant the entire container—bag, soil, and shoots—straight into the ground.
The rule for all container sizes—regardless of material—stays the same: select the right size container for the variety and number of carrots you’re growing and the space in which you will house the container(s).
Conclusion
As we have seen, you can start carrots indoors in bags, containers, trays, and soil blocks, even if you don’t have much space. After the seeds sprout, you can transplant them to an outdoor or indoor garden or grow them in the container they started in.
Bags make great containers to grow carrots in because they come in many sizes, and you can have as many bags or as few as you want.
Different carrot varieties have different planting and thinning requirements, but all need consistent moisture and light.
