ASK MARTHA: Container Gardening for Any Space

Garden Pots and Plans

Question: Hi Martha, I love growing my own plants, flowers and vegetables but don’t have space for a garden – what are my options? 

Martha: You don’t need a large yard to grow a garden of beautiful plants! The choice of plants for a potted garden is limited only by your imagination. Besides the usual annuals, there are flowering bulbs, perennials, ornamental grasses, shrubs, and small trees that all adapt well to a life of containment. And don't forget that growing herbs and crops like tomatoes and peppers in pots is perfect for small space gardening. For the greatest impact, select containers with a variety of sizes and shapes. When you stage them as a group, you can emphasize your best pots by propping them up on inverted pots or bricks. Potted plantings will give your garden remarkable flexibility -- it's easy to rearrange! Follow these steps to potted-plant perfection.

1. Pick the pot

Almost any type will do, as long as it has drainage holes. To protect the surfaces they sit on, raise pots on terracotta feet (available where you purchase your pots), wooden panels or bricks. Use repetition. Where a single potted plant might look insubstantial, a set of similar pots or planters packs a punch. Instead of setting one pot on your steps, for example, run a series up each side.

2. Select the spot

Read your plant’s labels to find their light requirements. For example, plants that need full sun, should be placed in a spot that receives six to eight hours of direct sunlight a day, whereas plants that tolerate some shade are great for porches.

3. Prep the soil

(See below for detailed instructions)

Potted plants need potting mix, a nutrient-rich type of soil specially designed for containers. You can find potting mix at any garden center or nursery. I prefer a rich, organic mix like Miracle-Gro® Performance Organics All Purpose Container Mix. First cover drainage holes with landscape fabric or broken ceramic (to keep soil from falling out), then moisten the mix before adding a layer to the pot, covering the bottom only.

4. Pot the plant

Loosen up the roots of the plant and suspend them in your pot to figure out how much more dirt you'll need to cover the roots; the leaves should appear just above the surface. Add enough soil so it's level and an inch shy of the container's rim. Pat down the soil firmly, then add enough water that it starts to drain through the holes.

5. Fertilize frequently

Unlike in-ground plants, those in pots have fewer nutrients to draw on (because of the limited amount of soil). Add a slow-release fertilizer 2 months after planting and follow the instructions for suggested feeding frequency during the growing season. Miracle-Gro® Shake 'n Feed® Extended Boost is a granular fertilizer appropriate for all plant types and lasts up to six months. 

6. Water well

You'll know the plant is thirsty when the soil feels dry an inch below the surface. Add enough so that the water starts to drain through the holes, but don't overdo it (or you'll also drain out nutrients). Never let the soil fully dry out.

7. Prune as needed

Some flowering plants require deadheading to encourage new growth; pinch or snip off dead blooms during the season. Those that are covered in small flowers, or that begin to wilt in late summer, should be cut back to one-third the size when the blooms are spent; don't worry, the plant will grow back in no time.

Martha's Container Tips

  • Plants may look a bit wilted during the hottest part of the day; this is their way of protecting themselves from excessive moisture loss. Don't allow plants to sit in water; empty their saucers after each watering and rainfall or rest the pots on stands.
  • It’s best that any container you use has several drainage holes in its bottom. Waterlogged soil is fatal to almost all potted plants.
  • Pack your pots. Put in three times the plants you think they can hold. Then feed them generously.
  • Consider using lightweight colored resin or fiberglass pots. They look like stone or terra cotta, but can help reduce the weight of container plantings, making them less of a load for decks and rooftops and easier to move on solid ground.
  • When plants outgrow a pot, move them to a pot just one size larger. "Overpotting" —setting a plant into a pot much larger than the root mass—will traumatize or even kill it.
  • Damp pots set flat on a deck surface promote wood decay. Raise them on terracotta feet or bricks to keep the deck surface dry.

Potting a Plant: Martha’s Step-by-Step Guide 

The way your plants are potted sets the tone for how they grow, so it's crucial to give them a good start. That means choosing both the potting mix and the pot with your particular plant in mind. 

General mixes, of course, are blended to accommodate the widest range of plant needs. Miracle-Gro® Performance Organics All Purpose Container Mix is a great all-purpose option. As for pots, remember that terracotta is a porous material that allows for good air flow and drainage, but it can dry out; plastic pots tend to retain more water. And container size is key. A good rule of thumb is to select one that is about an inch longer than the root mass.

1. It all starts with the potting mix. First, the moisture content needs to be right. To check the moisture level, take a handful of mix, and make a ball with your fist. When you open your hand, the mix should hold together and crumble loosely when touched. If it falls apart right away it's too dry; if water drips out from the ball, it's too wet.

2. Pick a pot whose diameter is about an inch larger than the plant's root mass and be sure it has a drainage hole. Cover the drainage hole in the bottom of the pot with a small shard of terra cotta to prevent the mix from washing out when the plant is watered. Then firm 1 inch of the mix into the bottom of the pot.

3. Center the plant in the pot so the roots can develop evenly all around. Place soil around the root mass, and gently firm it down with your fingers to eliminate air pockets. The plant's crown should be even with the soil level and about 1 inch below the pot's rim. This space will work like a water well when you water your plants and will prevent soil from washing out over the rim.

4. If your soil is more than 2 months old, improve your soil before use by working in time-release fertilizer at the rate recommended in the package directions.

5. Water your plant with a watering can or by bottom watering. In the case of bottom watering, place the potted plant in a tub or sink. Fill it with water halfway up the side of the pot. Water will wick up into the mix through the drainage hole in the pot's bottom. Check the soil surface for moisture. It should not take more than half an hour to saturate the mix. Remove the pot from its bath and allow excess water to drain out the bottom.

Article by Martha Stewart, as part of the Growing with Martha Stewart partnership.