This was a question that I thought a lot about when starting my container garden. Each plant that you grow needs the soil to be deep enough for its roots.

A container garden has to be deep enough for the plant’s roots to get sufficient growing space. Leafy vegetables can grow in containers 6-8 inches deep. Root vegetables need the container to be 8-14 inches deep. Fruiting vegetables can grow in containers 12-16 inches deep.

I’ll help you determine which containers you should pick for growing your plants based on their depth. I’ll also give you a long list of vegetables, fruit, and houseplants with the container depth you should use.

Why it’s important to give plants sufficient depth?

Plant roots are like fingers reaching down into the ground. They’re constantly searching for water and nutrients. If they don’t have access to these things, they won’t grow well.

Roots will only reach as far as the topsoil is thick enough to support them. The deeper the root system grows, the more food it gets from the surrounding area. This means that if you want healthy growth, you must provide plenty of room for the roots to spread out.

On average, doubling pot size allowed plants to grow 43% larger. – Science Daily

Why should you avoid giving plants too much depth?

It’s important to ensure the roots get the required depth in the container. But you don’t want to overdo this and use a container that is deeper than required.

This will make you use a lot of potting soil than is required. You need to spend more money than required due to this.

If the container contains a lot more potting soil than required, the roots may not be able to absorb all the moisture you provide. This will keep the potting soil moist for a lot longer, and you risk overwatering the plant.

Overwatering can cause fungal issues like root rot that can damage the roots and destroy the plant.

How deep should a container be for leafy vegetables?

Leafy vegetables such as lettuce require less depth than other types of vegetables. These include vegetables like lettuce, spinach, and kale. I’ve also included herbs like cilantro, mint, and lavender in this list.

You can provide 6-12 inches of depth in the container or growing bag, and they will grow just fine. You can grow several of them in a single container. You could even grow different leafy vegetables in the same container.

Here is a list of some leafy vegetables and the required container depth.

PlantContainer Depth (inches)
Arugula12
Bok Choy8
Cabbage12
Celery8
Chard6
Chicory18
Collards12
Kale12
Lettuce6
Mustard Greens6
Orach12
Sorrel8
Spinach6
Swiss Chard8
Cilantro8
Basil8
Lavender12
Rosemary12
Thyme6
Sage8
Mint12
Parsley8
Dill12
Fennel12
Chamomile8
Tarragon12
Oregano8
Marjoram6

How deep should a container be for root vegetables?

Root vegetables need a lot more container depth than leafy ones because their roots will grow deep into the soil.

Some of them, like turnips or beets, may need less than others, but on average, you need to grow them in a 6-24 inches deep container. I’ve also included tubers like potatoes and pods like garlic in this list.

You can grow different types of root vegetables in the same container if it’s large enough to give space for each of them.

Leave 3-4 inches of space between each plant, and adjust according to the seed package directions. (bhg.com)

Here is a list of some root vegetables and the container depth you should use.

PlantContainer Depth (inches)
Beets8
Carrots12
Garlic8
Horseradish24
Jicama12
Leeks18
Onions10
Potatoes15
Radishes12
Rutabaga12
Scallions6
Sweet Potatoes18
Turnips8
Chives8
Lemongrass8

How deep should a container be for fruiting vegetables?

These types of vegetables tend to need the most container depth. They have deep roots and grow tall, so they need this depth.

You need to provide a container with 8-12 inches depth for growing fruiting vegetables such as tomatoes, peppers, cucumbers, and eggplants. I’ve also included vegetables like asparagus and Brussels sprouts in this list.

You should not grow different fruiting vegetables together because they will compete for nutrients and moisture, affecting growth.

Here is a list of some fruiting vegetables that you can grow and the container depth they need.

PlantContainer Depth (inches)
Asparagus12
Beans8
Broccoli8
Brussels Sprouts12
Cauliflower8
Corn12
Cucumbers12
Eggplant12
Endive6
Kohlrabi16
Okra10
Peas8
Peppers10
Pumpkins20
Rhubarb20
Squash12
Tomatoes12
Zucchini12

How deep should a container be for houseplants?

Houseplants can vary a lot in their size, and you need to find out the depth requirements for each plant.

The good thing about houseplants is that you can grow them in any decent depth container, which will do fine. That’s because you’re not expecting edibles from them.

You will do fine if you pick a container between 8-12 inches deep when growing houseplants.

Do use your judgment to figure out how deep the container should be. Small plants like succulents could do just fine in containers with less depth, such as 4-6 inches.

If you’re growing flowering plants, you should note that perennials will need deeper containers than annuals. That’s because their roots grow deep into the soil to survive for years, unlike annuals.

Here’s a list of some houseplants you may grow and the container depth you can use.

PlantContainer Depth (inches)
Anthurium8
Croton12
Orchid6
Pothos10
Red Aglaonema6
Snake Plant10
Peace Lily10
Succulents4
ZZ Plant10
Ponytail Palm8
Chinese Evergreen8
Grape Ivy8
Philodendron12
English Ivy8
Spider Plant6
Hoya8
Rubber Tree10
Cast-Iron Plant8
Jade Plant12
Weeping Fig8
Asparagus Fern6
Chinese Money Plant6
Yucca10
Air Plant6
Aloe4
Dragon Tree12
Calathea10
Bromeliad6
Kalanchoe6
Crown Of Thorns8
Christmas Cactus6
Schefflera10

How deep should a container be for fruit plants?

You can grow some fruits in containers, such as strawberries, blueberries, and even figs.

But some of the fruiting plants grow into trees, and even if you grow some dwarf ones in the container, they could require a lot of depth.

You may need a container 8-48 inches deep if you want to grow some of the fruiting plants and trees.

Here are some fruit plants and the container depth you need for growing them.

PlantContainer Depth (inches)
Melons16
Strawberries8
Blueberries24
Pineapple24
Cantaloupe16
Watermelon20
Currants20
Gooseberries18

Difference between a container and grow bag for plant depth

You can use either a container or a grow bag to grow your vegetables, houseplants, and fruits. The benefit of using grow bags is they are lightweight, inexpensive, durable, and allow the roots more breathing space, so they don’t get root-bound.

The grow bags have a thin boundary compared to containers. They also tend to hold more potting soil than containers. This means you can use less potting soil in a grow bag than in a container.

It would be fine to use 1-inch less depth in a grow bag compared to a container. That would be sufficient to meet the depth requirements of the plant.