Companion gardening lets gardeners grow several plants together to draw beneficial insects and take advantage of compatible growing conditions. While many different species can grow alongside each other just fine, some couplings make life difficult for each other.
You cannot plant celery with carrots in the same soil because they will suffer from resource competition. The two plants mature at different rates and will likely experience greater-than-usual pest infestations due to multiple common pests.
This article will show why celery and carrots cannot grow together outside. We will also explore a few options for finding a way to grow them together after all, just maybe not in the way you’d expect.
There’s Not Enough Room in the Soil for Both of Them
Carrots and celery can develop a bit of a sibling rivalry over public space, not unlike human siblings. They live in the Apiaceae family of plants, including the healthy parsnip and the deadly hemlock.
While the carrots have matured by harvest time, the celery develops a little slower than its sibling, so unearthing them risks damaging the celery roots. When you pull a vegetable the size of a carrot from the garden, it shifts the soil around it, sometimes severing neighboring roots.
Harvesting carrots from celery-occupied soil exposes the fragile celery roots to sun and insect damage. When you harvest a carrot, you need to use a tool to loosen the surrounding soil, increasing the risk of cutting or damaging celery roots.
Since outdoor gardens live at the mercy of seasons and weather, you only have so many ways to control the process.
Shared Pests Harm Both Plants
If one crop attracts pests, gardeners often plant another kind of crop that draws beneficial critters to attack the invaders, either eliminating them or reducing their numbers.
Some varieties of herbs, fruits, flowers, and vegetables can even repel pests, creating an invisible force field around the garden. For example, some insects find the smell of garlic or onions repugnant and, therefore, won’t go anywhere near them.
However, intercropping or companion gardening can bring disastrous results in carrot and celery cases. Since celery and carrots share multiple pest concerns, the threat of one harmful insect or microbe species can double, resulting in an overwhelming infestation.
Here are six examples:
- Cutworms: As the name suggests, cutworm larvae use their mandibles to cut through young vegetable shoots above the soil, damaging the plant and disrupting growth. Several species of these moth caterpillars attack the foliage and fruit of mature crops.
- Carrot Flies: The maggot versions of these flies infest celery, carrots, and other vegetable roots and root vegetables, making Swiss cheese out of everything and killing the entire plant.
- Aphids: These tiny pests not only inflict direct damage to plant tissue when they feed on it but also produce toxins that infect the primary plant and can be passed to other crops.
- Root Knot Nematodes: Tens of thousands of nematode species exist, and many of them benefit your garden. The Root Knot type, on the other hand, hurts your crops by draining nutrients (and therefore flavor and consistency) from the veggies, causing wart-like bumps and hairy lateral roots to proliferate all over the vegetable. To learn more, you can read this article: Can You Still Eat Bumpy Carrots?
- Leafminers: The term ‘leafminers’ refers to a large group of various fly larvae. The adult flies lay eggs underneath the leaf surface where the larvae hatch. The larvae then chomp a path underneath leaf surfaces, inflicting damage to leaves and diminishing crop yield until they reach the pupa stage.
- Carrot Weevils: Topping out at one-quarter of an inch in length, you might be able to find adult weevils in the garden and try to control the situation by hand. But if you plant celery and carrots together, you can expect to double your workload—carrot weevils love celery as much as they love carrots. Their damaging larvae (again with the larvae!) perforate the roots, which kills the plant.
Grow Carrots and Celery Together Inside
While we can’t grow carrots and celery together outside, we do, however, have the option of growing them together inside, albeit in separate soils. You can grow them in individual containers like plastic pots or in an Aerogarden.
Not only will indoor growing avoid the problems of co-planting them, but it also grants you more precise control over how much water and nutrition each receives. Your thermostat sets the temperature, your blinds or grow lamps set the light, and you determine the watering schedule.
When growing these plants indoors, you have two main options: soil-filled containers or a hydroponic system like the Aerogarden.
Grow Them in a Container
If you want larger carrots, you must use bags or containers. Container plants can share the same light source but not the same soil or water (Rube Goldberg-esque workarounds notwithstanding).
Growing indoors eliminates the need to rely on the seasons for timing and harvest. Celery is ready 85–120 days after transplant. Carrots are ready between 70–80 days.
Not all varieties will mature simultaneously, so adjust your times according to your variety’s schedule. You can improve your accuracy by controlling the light, water, and food conditions.
It will take experimenting with your varieties to get the particular timing down, but based on the 70–80 day estimate, you could, for example, plant the celery on Day 1 and the carrots on Day 20, then note how long it takes for them to mature. This way, you can harvest them in the same week or even on the same day.
Celery performs well in plastic or glazed clay pots and bags. Fabric grow bags, or porous clay pots don’t have a vapor barrier, so they allow too much moisture to pass through the sides, causing the soil to dry out faster.
Celery works well in plastic bags that retain a little moisture because celery prefers humidity and abhors drought.
Carrots also thrive in bags (including fabric) but don’t like as much moisture, which is easy to control indoors. You could put a plastic bag with celery next to a fabric bag with carrots, and both would produce healthy yields.
Carrots need lots of room below the soil line, so they do much better in deep pots; however, smaller varieties exist that grow unimpeded in smaller pots. The container material matters less for carrots because they tolerate drier soil, but avoid overwatering if you’re using glazed containers or non-perforated bags.
Grow Them in an Aerogarden
If you want only small harvests or don’t mind small carrots, you can grow them beside celery in an Aerogarden. An Aerogarden allows smaller quantities to share the same light source and water; most models take up less space than multiple containers.
The Aerogarden uses a hydroponic watering and feeding system that pumps air into a water basin built underneath a growing tray. Mounted lights at the top of the garden can adjust up or down based on plant height.
Each plant has its own growing basket filled with growing medium to germinate the seeds and stabilize the shoots. The bubbling water underneath the basket supplies water and nutrients to the hanging roots.
Celery grows well in an Aerogarden because it does not require as much space below the soil line and prefers moister soils. Since Aerogardens use hydroponics to feed and water the plants, the celery receives plenty of moisture and nutrients.
When growing carrots in an Aerogarden, you want to choose one of the smaller varieties that can mature without crowding pressure from the basket. Celery variety comes down to preference because they only need a few inches of surrounding growing space.
As we explored above, carrots and celery cannot be planted in the same soil. Planting them in separate containers indoors eliminates the pest problem while preserving the culinary benefit of growing them simultaneously. The Aerogarden makes a great indoor growing option as it removes the pest concern and gives each plant space while sharing the same light and water.