Whether you are growing in a raised bed or pots, the amount of soil and its depth are limited. So, when choosing what plants to grow you need to think how deep the roots of different plants will grow. Also, an important consideration is the size of the plant once it’s mature. Most of the plants can grow in 12 inches of soil.
However, you will be surprised to know how many plants can grow in only 6 inches of soil. Moreover, the top 6 inches of soil are packed with nutrients that plants need for healthy growth. Although most vegetables form roots within top 6″ of soil, others need to send their roots deeper.
That helps to secure the plant, making sure that it is not going to fall over when it is windy or when the soil is too wet. In addition, deeper soil means more nutrients and trace minerals. Hence, plant growth increases. So, it is better to choose a bigger pot or dig a deeper raised bed.
There are three types of plants depending on the soil depth requirements: shallow rooting, medium rooting and deep rooting. Shallow rooting vegetables grow in 12″ – 18″ of soil. Medium rooting plants need 18″ – 24″ of soil. And, finally, deep rooting benefit from soil depth starting from 24″ and onward.
So, what plants can grow in 12 inches of soil?
Herbs: Arugula, Bay, Basil, Chives, Cilantro, Mint, Oregano, Parsley, Tarragon, Thyme, Turmeric.
Vegetables: Broccoli, Brussels sprouts, Beetroot, Bok choy, Cabbage, Cauliflower, Carrot, Celery, Celeriac, Chinese cabbage, Corn, Endive, Fennel, Garlic, Ginger, Kohlrabi, Kale, Leeks, Lemongrass, Lettuce, Mustard Greens, Onions, Potatoes, Radish, Rhubarb, Scallions, Shallots, Spinach.
Fruits: Blueberries, Currants, Gooseberries, Kiwi, Raspberry.
What vegetables grow in 12 inches of soil?
Broccoli – sow seeds ¼ to ½ (6-13 mm) inch deep and 3 inches apart. Plant broccoli just an inch deeper than their normal growing depth. Broccoli’s size at maturity is 18″ – 24″.
Brussels Sprouts – sow seeds ½ (13mm) deep. Once the seedlings are 5-7″ tall, space them 2 feet apart. Plant them deeper that they grew, so that the lowest leaves are just above the ground. Their size at maturity is 24″ – 36″.
Beetroot – sow seeds 3/4 (2cm) deep and 2 inches apart. Once the seedlings are 3/4 inches (2cm) high, space them out leaving one beetroot seedling every 4 inches (10cm). Its size at maturity is 8″ – 12″.
Bok Choy – sow seeds ¼ to ½ inch (6-13mm) deep and 2 inches (5 cm) apart. Barely cover them with soil. Thin the seedling to 8 inches (20 cm) apart. Its size at maturity is 12″ – 24″.
How deep does soil need to be for cabbage?
Cabbage – sow seeds ½ inch (13mm) deep and 1 inch apart. Thin the seedlings to 18 to 24 inches apart. Its size at maturity is 12″ – 18″.
Cauliflower – sow seeds ¼ inch (6mm) deep. Thin the seedlings to 6 inches apart. The distance between plants determines the size of the heads. Its size at maturity is 12″ – 30″.
Carrot – sow seeds ¼ inch (6mm) deep and 2-3 inches apart. Carrot seeds are tiny, so you need to sow the shallowly and thinly. If you sow thinly, you are avoiding thinning out. Its size at maturity varies between 6″ – 15″ depending on the shape.
How deep to plant celery seeds?
Celery – celery seeds are tiny, so you need to take a pinch and lightly sow them across the level seed compost. Once the seedlings are 3″ (8cm) tall, transplant them outside. Plant celery seedlings 11 inches (27cm) apart to ensure that each plant grows with lots of well-branched sticks. Its size at maturity is 18″ – 24″.
Celeriac – sow seeds ⅛ inch (3mm) deep or sprinkle the seeds over the tray with seed compost. Don’t cover them with soil as they need light to germinate. Space out the seedlings 6-12 inches (15-30 cm) apart. Its size at maturity is 4 to 5.5 inches (10 to 14 cm) in diameter.
Chinese cabbage – sow seeds ¼ to ½ inch (6-13mm) deep and 10 inches apart for upright varieties. If you are growing spreading Chinese Cabbage you need to plant seeds 18 inches apart. Its size at maturity is 12″ – 24″.
Corn – sow seeds 1.5 to 2.5 inches deep and 4 to 6 inches apart. You need to plant seeds at the same time so every plant has an equal opportunity to compete maximizing yield. Its size at maturity is 4′ – 8′.
How deep to plant endive seeds?
Endive – sow seeds ½ inch (13mm) and 1 to 2 inches (2.5-5 cm) apart. The rows should be 12 inches (30cm) apart. Thin the seedlings to 9-13 inches (23-38cm) apart within the row. Its size at maturity is 6″ – 9″.
Fennel – sow seeds ½ inch (13mm) deep with 3 to 4 seeds every 10 to 12 inches (25-30cm). When the seedlings are 4 to 6 inches tall thin them so the plants are 12 to 18 inches apart. When fennel is mature its stalk is at least 3 inches in diameter and the leaves are 18 inches tall.
Garlic – plant cloves 1-2 inches deep and 9 to 12 inches apart. Its size at maturity is 12″ – 24″. Also, you need to keep in mind what to plant after garlic to maintain crop rotation.
Ginger – break up the ginger rhizomes in little pieces so each of them has a couple of growing buds. Plant these pieces 2 to 4 inches deep and 8 inches (20 cm) apart. Its size at maturity is 2′-3′.
How deep to plant kohlrabi seeds?
Kohlrabi – sow seeds ½ inch deep and 1 inch (2.5 cm) apart. The rows should be 12 inches (30cm) apart. Thin seedlings to 5-8 inches apart withing the row. Its size at maturity is 9″ – 12″.
Kale – sow seeds ¼ to ½ inch (6-13mm) deep and 4 inches (10cm) apart. Thin the seedlings to 8-12 inches apart. Its size at maturity is 12″ – 24″. If your Kale is too tall it can be due to bolting.
Leeks – sow seeds thinly ¼ inch (6mm) deep and 1 inch (2.5cm) apart. Cover the seeds in drill with fine sifted soil. Its size at maturity is 12″ – 24″.
Lemongrass – sow seeds thinly ¼ inch (6mm) deep and 1 inch (2.5cm) apart. Cover the seeds with soil and mist well. Its size at maturity can reach 5′.
Lettuce – sow seeds ¼ to ½ inch (6-13mm) deep and the rows should be 12 inches (30cm) apart. This the seedlings when they have 3-4 true leaves. Its size at maturity is 6″ – 12″.
How deep do you need to plant mustard greens?
Mustard Greens – sow seeds ½ (13mm) deep and 6 inches apart. Once they sprout, thin seedlings to 3 inches apart. Its size at maturity is 3′.
Onions – sow seeds 1 inch (2.5 cm) deep and at least ½ inch (13mm) apart. The rows should be 8 inches (20cm) apart. Thin the seedlings to 2 inches apart and later to 4 inches apart. Its size at maturity is 8″ – 24″.
Potatoes – dig 4 inches (10cm) deep trench and place potatoes with the rose end pointing up 12 inches (30 cm) apart. Trenches should be 2-3 feet (0.5 to 1 m) apart. Potatoes size at maturity is 12″ – 30″.
Radish – sow seeds ½ inch (13mm) deep and ½ (13mm) apart. Cover the seeds with soil and water well. The rows should be 6 inches (15cm) apart. Its size at maturity is 2″ – 6″.
How deep do you need to plant rhubarb?
Rhubarb – you can grow Rhubarb from seeds, but it is easier to plant dormant crowns. Plant Rhubarb so the tip of the crown is just visible above the soil and space crowns 30-36 inches (75-90cm) apart. In addition, the space between rows should be 12 inches (30cm). Its size at maturity can reach 6′.
Scallions – sow seeds ¼ inch (6mm) deep and ½ inch (13mm) apart. The rows should be 12 to 18 inches apart. Its size at maturity is 1′-3′.
Shallots – sow seeds thinly ½ inch (13mm) deep in rows 12 inches (30cm) apart. Thin seedlings to 1-3 inches (2.5-7.5cm) apart. Increase the spacing if you want an individual shallot to grow bigger. However, it is easier to plant shallots from sets.
Plant shallot sets 1 inch (2.5 cm) deep and 10 inches (25cm) apart in rows 16 inches (40cm) apart. Shallots growing from sets mature quicker and grow better in cold regions. Moreover, they are less likely to be damaged by pests or diseases. Shallots size at maturity is 8″.
Spinach – sow seeds 2/5 inch (1cm) deep and 1 inch (2.5cm) apart. The rows should be 12 inches (30cm) apart. Water the seeds gently and let the water to drain away. Its size at maturity is 6″ – 15″.
If you want to know the size of a pot or a container for growing vegetables, check out this blog post. However, if you are building a raised bed in a greenhouse or your garden, check out this article.
What plants did you grow in 12 inches of soil? Let me know in the comments section below!
Happy Growing!
