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Pick a Pot
by Chris Eirschele - posted 01/16/18

 

 

 


 

Small, large, wide, narrow, made from metal, wood, plastic, stone or clay—the humble container is the foundation of the celebrated container garden. Here are some tips on choosing just the right vessels. 

 


The pot, which holds the soil and plants, is the foundation of any container garden. As container gardens have exploded in popularity, there is simply no longer just the clay pot in which to grow a pansy. Complicating the picture is the myriad of plants hybridized to grow in the limited space of a container garden.

Containers for growing plants can be made from metal, wood, plastic, stone or clay. The planter may be as big as a 4-foot-tall urn or as tiny as a 4-inch-diameter saucer. Pots can be porous, quickly drying out in hot summer sun, or impervious to water, creating an unintended boggy garden.
 

A single embossed urn planted with simple yellow pansies is still able to make a dramatic focal point, easily drawing the eye to that part of the garden.

Location, Style and Plant Favorites
When planting a container garden, gardeners may think it is a matter of deciding which is first—the pot or the plant. Consider the style and space for a container garden and then the type of plants one chooses to grow.

The location will determine the container garden. Is it on a windy balcony or set on a grassy surface? One rustic whisky-barrel, cut in half, can hold a small, but still weighty perennial bed or child’s vegetable garden. A mammoth plastic pot can be a water garden but still requires occasional draining. On the other hand, a collection of 6-inch clay pots or metal containers of assorted sizes can become a container garden, too.

These days, the selection of plants for containers is rarely regulated to traditional annuals or the odd houseplant summering outside. Plant breeders have introduced gardeners to dwarf perennials, miniature evergreens and determinate vegetable plants purposely bred to thrive in confined environments, sometimes for more than one growing season.
 

Making Drainage Holes in a Container

Containers without holes for drainage require gardeners to answer some questions: Is the container necessary in a garden? Is it worth the potential cracking to make a hole? Is it possible to use the container as a decorative cover (for example, a nursery pot within the pot)?

Here are some tips for making a drainage hole in a pot:
•  Create a ¾ inch diameter hole for every square foot of base for good drainage.
•  Drill approximately 1 foot up, on each side for containers that will be set on the ground.
•  Choose three smaller, well-spaced holes over one large hole.
•  Make the holes with a nail or a pickax on metal containers.
•  Use a drill with a standard bit for wooden surfaces.
•  Use a masonry drill bit on stone and terra-cotta (wet the surface first).

Choosing Container Materials
Gardeners should think about the material of their containers. This will help determine how they might have to adjust their watering routine (porous or impervious) and which plants benefit from what type of container materials (plants that like dry conditions versus boggy sites).For example, the short-rooted sedum is traditionally planted in 4-inch-deep saucer-styled clay pots, which ensures that the roots will not become water logged. The porous material of clay or terra-cotta will dry out faster under full summer sun, and for succulent plants this is a good thing. However, a planter growing vegetables all summer will benefit from a hard plastic material inhibiting the quick loss of moisture.

Eclectic containers or pots not originally intended for growing plants present the greater challenge, not only for their material and structure but for their size. Very tall urns may have been created for indoor use when originally made, while original metal watering cans and stone troughs had an entirely different purpose at the outset.

 

Clay pots are the traditional container used for many centuries to grow plants where no planting bed is available. Accumulation of salt and cracking are two disadvantages for using this type of material. • A collection of eclectic containers to hold soil and plants is an informal garden style often found in cottage settings. A bushel basket is an inexpensive, albeit unusual, container but effective when lined with plastic that has been punched with holes. • A plastic green flower box with a tray is a versatile container for growing plants indoors, as well as outside. Placed on a solid surface outdoors, the tray can be turned upside down. This allows the water to drain away from the bottom but not damage a deck or patio surface.


Right Plant in The Right Pot
Gardeners will want to determine container size needed to maintain the health of the plant and for aesthetic appearance, a version of “right plant, right place” or in this case, right size pot. For health reasons, the container needs to be big enough for the roots to grow, for soil to be added and plants watered. Containers that are too large inside can be adjusted by altering the planting space and filling the lower section with Styrofoam peanuts, newspaper or a false bottom. Plants in too small of a pot will quickly outgrow their space; a conundrum solved only by potting the plants in a larger pot or allowing them to die.

No matter how simple the container garden, gardeners take pride in the appearance of their plants. Choosing the correct style and color of a container is part creative license but scale between pot and plant may be more than just good looks. A tall evergreen in a container less than 24 inches in diameter and height will not have much space to thrive, while a good gust of wind is liable to topple it.


A flower garden in one pot is filled with Calibrachoa, Lantana, Bacopa and a trailing licorice plant
 

A combination of perennials and annuals in a mixed planting has become a popular idea for the summer garden. It is not unusual to see three or five quart-sized plants at the local garden center crammed into a stylish container. Unless the gardener is changing out some of the plants mid-season or the planting is meant for a one-time event, if the idea is appealing, consider starting with a larger container and staging them together each in their own pot or starting with smaller transplants.
 

Iron hay racks and hanging baskets are lined to hold in soil. The liners can be made of coconut husks or sphagnum moss, making the container extremely porous but aesthetically attractive. A plastic liner with drainage holes can also be added between liner and soil to hold in more moisture.

Water Drainage
The most important feature of any outdoor container is its ability to drain water. Iron hanging baskets and hay rack planters are made to be used with liners that do not require making holes; the liners made of coco husks are very porous. In most containers, though, drainage holes are necessary for growing plants successfully.

Generally, holes are placed at the bottom of a container. Some manufactured containers will have a plug installed, giving the gardener the option to remove it; do not forget to do this before adding soil. Wooden barrels or baskets have uneven openings between slats or weaving; in this case, gardeners will have to decide if a plastic lining is needed to hold in soil; if so, holes should be punched into the lining.

Containers set flush on the ground present a particular issue. That is, of water soaking back up into the container when too much water is flowing out too fast. Where possible, drilling holes on each side of the pot will improve this situation. A second remedy is to rest the pot on a set of cement steppers (or pot feet) to provide open space between the container and the ground.
 

Overwintering Pots Outside
Gardeners who live in cold regions (like Zones 5 and 6) and keep their containers outside have special challenges in maintaining a container garden. A simple solution is to only grow plants that live one growing season and empty then store all containers in the basement or garage until spring. Plants like coleus and annual geraniums can be propagated and overwintered indoors and entire tropical plants can be moved indoors to a sunny window.

But for gardeners who want to push the proverbial envelope, some plant lovers employ strategies designed to improve their chances of keeping perennials from one year to the next. Choose the hardiest perennial species or cultivar for the region, water well before the first frosts appear and move the pot to a protected location. Wrapping pots in bubble wrap and burlap, and banking around the container with mulch or straw bales are other useful tactics.

Container gardens are a viable option to grow a plant collection, whether it is for ornamental value or as a source of fresh food. The right pot, planter or basket is the foundation to creating a thriving garden.

 

A version of this article appeared in a January/February 2011 print edition of State-by-State Gardening.
Photography courtesy of Proven Winners, Chuck Eirschele, and Chris Eirschele.

 


Chris Eirschele is a freelance writer and author who has advocated container gardening since her days as a Master Gardener in her native Wisconsin. Visit chriseirschele.com and her blog at staygardening.com.