Interplanting Vegetables: Root Depth, Plant Height

Crop interplantingInterplanting is a growing method that will allow you to fit more vegetable plants in a single planting bed. It is a way to increase your crop yield. Interplanting is also called intercropping.

Interplanting is often used in intensive vegetable gardening where an effort is made to use all available space in the growing area–the counter point to single row planting which requires the most cropping space since the space between rows goes unplanted. (In intensive gardening you can space plants individually equidistance apart or in wide rows–several plants across a row to as much as 4 feet wide.)

There are several ways to interplant your crops. You can grow fast-maturing plants, such as radishes, between slower growing ones, say chard. The radishes will be ready for harvest before the chard begins to mature and requires more space to spread out. This way of interplanting borders on succession cropping–bringing one crop to harvest after another keeping the planting bed productive all season.

You can also interplant crops with different growing habits, tall crops near short ones, or deep-rooted with shallow-rooted. Crops interplanted by growing habit can be set equidistant according to their size (height and breadth or root depth) at maturity; or they can be planted in their own alternate rows in a wide bed.

Interplanting requires planning. You need to know the days to maturity for each crop and its height and breadth at maturity or its root depth at maturity. Do some planning on paper once you have decided on the crops you will be growing this season.

To assist your planning here are two charts that might help: one for plant height at maturity, one for rooting depth (For additional information on vegetable crop root development, see the 1927 book “Root Development of Vegetable Crops” by John Weaver of the University of Nebraska.):

Root Depth

Shallow Rooting (18 to 36 inches)
Medium Rooting (36 to 48 inches) Deep Rooting (more than 48 inches)
Broccoli  Beans, snap  Artichokes
 Brussels sprouts  Beets  Asparagus
 Cabbage  Carrots  Beans, lima
 Cauliflower  Chard  Parsnips
 Celery  Cucumbers  Pumpkins
 Chinese cabbage  Eggplant  Squash, winter
 Corn  Peas  Sweet potatoes
 Endive  Peppers  Tomatoes
 Garlic  Rutabagas
 Leeks  Squash, summer
 Lettuce  Turnips
 Onions
 Potatoes
 Radishes
 Spinach

Plant Height

Tall Medium Short
 Beans, pole  Anise  Basil
 Broccoli  Artichokes  Beets
 Corn, sweet  Broccoli  Borage
 Fennel  Brussels sprouts  Cabbage
 Mustard  Lemon balm  Caraway
 Okra  Beans, bush  Carrots
 Peas  Broccoli  Cauliflower
 Sunchokes  Brussels sprouts  Celery
 Tomatoes  Cardoon  Chervil
 Chard  Chives
 Chinese cabbage  Corn salad
 Collards  Dandelion
 Coriander  Endive
 Cucumber  Garlic
 Dill  Kale, dwarf
 Eggplant  Kohlrabi
 Hyssop  Leeks
 Kale, curled  Lettuce
 Lavender  Onions
 Marjoram  Parsley
 Peas, dwarf  Parsnips
 Peppers  Radishes
 Potatoes  Rutabaga
 Pumpkins  Savory
 Rhubarb  Thyme
 Sage  Turnips
 Spinach
 Squash
 Sweet potatoes