Container Gardening Basics

Choose the Right Container
Outdoor containers should:

  • Be at least 14-18” across otherwise they can dry out too quickly (indoor containers can be much smaller but will require more frequent watering)
  • Have adequate drainage (holes should be between ½ and 1” across, large pots should have multiple drains)—when planting, cover holes with fine screen, cheesecloth or coffee filters to keep soil from running out of the holes
  • Suit the size of the plant (or plants) that are going into them

Containers come in a variety of shapes and materials, which you choose are a matter of taste, style and how you plan to use it. Learn more about Choosing Containers.

Don’t Scrimp on Soil
Choose a soil mixture that:

  • Drains well so plants don’t get waterlogged
  • Holds enough moisture so plants don’t require constant watering
  • Is organic—everything that goes into the pot goes into the plant and will eventually wind up on your plate
  • Has the right pH—most vegetables prefer a slightly acidic soil (5.5-6.5), however blueberries require an even more acidic soil with a pH of  4.5 to thrive

For vegetables, add extra compost (up to 25%) so your plants have what they need to produce in abundance.

Pick the Right Plants
When selecting individual plants:

  • Size matters—always take into account the mature size of any plant before you put it in a pot, especially if you’re planting trees; make sure you stick with dwarf and/or slow growing varieties so they don’t outgrow their new home too quickly or crowd out other plants
  • Buy big—the larger the individual plant (say, a 1 gallon vs. a 4” pot) the more well-developed the roots
  • Consider the cold—in a container, a plant’s hardiness decreases by about 10 degrees (sometimes more in smaller pots); a plant that may ordinarily handle your winter quite well might not have the same success in a pot

When determining which plants go together:

  • Make sure they have compatible needs in terms of water, sun, soil pH, etc.
  • Coordinate plant heights—include something tall, a few things mid-range, a few more small and of course, some trailers to hang over the edge of the pot
  • Keep the pot’s location and planting design in mind—taller plants may cast shade on lower level sun-lovers or a building may block light from one half of the planter

Water Wisely

  • Keeping your containers appropriately watered is crucial to plant survival. Pots can’t hold as much wateras a planting bed while inadequate drainage may keep water trapped.
  • Check daily in hot weather—when the mercury rises, your plant’s water needs increase, and without the buffer of a large garden bed, to keep them cool and damp, sometimes it takes only hours to permanently damage a heat-sensitive plant
  • Dig deeper—don’t just rely on how the soil looks, dirt dries out fastest at the top of the pot so be sure to stick your finger at least one inch into the soil to test its true moisture content
  • Elevate your pots—putting containers on risers helps water drain and air circulate and protects your patio surface from water damage; you can purchase decorative pot feet in most garden centers, but bricks work just as well
  • Consider irrigation—container watering systems cost some money up front, but they will save you time, worry, and the cost of replacing lost plants; they are also invaluable for vacation care
  • Don’t forget the mulch, it helps retain moisture and helps keep roots cool in hot weather

A Few Other Tips

  • Place a saucer below pots on a wooden deck to prevent the deck boards from rotting
  • Consider placing heavy containers on rolling plant caddies so you can move them more easily—especially helpful in climates where tender plants need to be moved indoors for the winter