Successful Container Gardens
- Welcome to the World of Container Gardening
- Choosing a Container
- Selecting Soil Mixes
- Considering Environmental Factors
- Creating Four Season Containers
- Choosing and Combining Plants
- Making Herb and Vegetable Container Gardens
- Grooming Basics
- Building Successful Containers
- Blueprints for Building Containers
- Troubleshooting Cultural Disease and Insect Problems
- Constructing and Caring for Container Water Gardens
- Making Hanging Baskets
- Landscaping with Containers
- Growing Vines in Containers
- Overwintering Plants and Containers
- Container Garden Whimsy
- Water Gardening
- Beyond Impatiens and Petunias
- Tropical Punch
Choosing a Container for Planting
Drainage Is Critical to Plant Health
A hole at the bottom of the container is critical. It allows water in the soil to drain freely so adequate air is available for the roots. While various kinds of plants have differing drainage needs, few can tolerate sitting in stagnate water. Healthy roots mean healthier plants. So be sure there are holes for drainage. Shoreline plants love wet soil, so if the pot does not drain, consider using them. See the water gardening section for more information.
Wet soils favor root rot, because they leave little space for air to get to the roots. Plants rarely recover from root rot. More information on root rot:
If the pot does not come with a hole in it, figure out a way to make a hole. One way is to drill one. Some decorative resin or plastic pots have pre-punched holes at the bottom for easy removal. Generally, very little soil falls through the hole. To keep soil from falling through large drainage holes some folks use a coffee filter paper over the hole, though this is not necessary. Small holes in the bottom of the pot allow the water to drain out and very little soil media is lost.
Sometimes a plant is already planted in a pot with no drainage at all. The best solution in this case is to take it to a sink, water it, then after a few minutes turn it on its side for a minute or two to let excess water drain out.
Beware of pots with permanently attached saucers where emptying the overflow is difficult or impossible. I learned this the hard way when my basil leaves turned black because the roots were waterlogged – the result of a permanently attached saucer. Drainage of excess water is vital for the health of plant roots. It is much better to use a pot with a detachable saucer. Be sure to empty the excess water so soils have an opportunity to dry out somewhat.
Slipping a container inside a slightly larger one is called double potting. When double potting is used, the plants grow in a pot liner. Often this is a plain plastic pot. This allows you to slip the pot liner in or out of the decorative container without disturbing the plant roots. Check to be sure that the plants in the pot liner never stand in water (unless you have aquatic plants) If water accumulates in the bottom of the larger container, remove the inside pot and drain the water from the outside pot. Place gravel in the bottom of the outer pot if the decorative pot is deep enough. A little excess water can accumulate in the gravel without the plant roots having to stand in water.
Double potting techniques may be used:
- to overcome the problem of no drainage hole in an attractive decorative pot;
- to quickly change seasonal displays;
- to combine plants with different environmental requirements;
- to minimize extreme soil temperature fluctuations;
- to keep desirable but invasive plants from spreading.
Skip the gravel inside the bottom of individual or pot liners
It is a myth that a layer of gravel (inside the bottom of an individual pot) beneath the soil improves container drainage. Instead of extra water draining immediately into the gravel, the water “perches” or gathers in the soil just above the gravel. The water gathers until no air space is left. Once all the available soil air space fills up, then excess water drains into the gravel below. So gravel in the bottom does little to keep soil above it from being saturated by overwatering.
Damp gravel placed in a saucer underneath the pot may help by increasing the humidity in the immediate area of the plants as the water evaporates from the gravel surfaces.
More info about gravel in bottom of a pot can be found at: http://www.puyallup.wsu.edu/
Self-watering pots use various methods to effectively draw water from a bottom reservoir into the soil without causing the soil to become too wet. Water may be drawn up into the soil by capillary action (or wicking) through small soil columns, rope wicks, or the use of moisture sensors. Self-watering containers are especially useful for weekend cottages and people who do not have time to check water needs daily.
Consistently available water is great for vegetables, and tropical houseplants. Imagine a dozen stalks of sweet corn producing ears on your patio in a self -watering container like the Earth Box™. Plants that need to dry out like thick-leaved cactus and succulents do not usually warrant the extra cost of a self-watering container.
For more information, use a web search engine using the keywords “self-watering planter” or “self-watering container” or “earth box.”
Decorative pots and wraps without drainage holes. Sometimes you fall in love with a wonderful container that has no drainage hole. This would be the perfect time to find a pot liner to fit inside so both you and the plants are happy. In addition to decorative pots, decorative foil or plastic pot wraps are a form of double potting. The wrap keeps water from leaking out where it is not wanted. To protect the plant from becoming prone to root rot, pierce a hole in the bottom of the wrapper or foil. Then place the container on a saucer. Or, take the container to a sink, remove the wrapper, and then water. Let the water drain freely out the holes in the bottom of the pot. After the pot finishes draining, replace the wrapper.
Changing seasonal displays. Double potting makes changing out seasonal plants a breeze. Fresh plants are easily rotated in and tired ones out of a large landscape container holding multiple plants. Double potting makes it possible to sink individual potted plants into the landscape (or remove them) without disturbing the roots.
Combining plants with differing requirements. Plants that have different soil drainage (aeration) requirements can be combined in a landscape planter if they are in their own separate pots. This allows different watering practices for each plant. On the other hand, if there is not enough light, two sets of plants can be used. As individual plants begin to decline, rotate them back to a higher-light nursery. Replace them with healthy plants. It is less work to choose plants with similar environmental needs or ones well adapted to conditions available. However, this is not always possible.
Reducing fluctuation of soil temperature. Roots are generally more susceptible to cold damage than stems and leaves. When overwintering an otherwise hardy plant, sink the potted plant into the ground. Then mulch over the soil with wood chips, soil or other material to help it survive winter. The soil temperature underground does not fluctuate like container soil which is exposed to wind and extremes of temperature.
Restraining invasive plants. Some plants are attractive, but spread invasively by underground roots. They invade space that does not belong to them. For example, most people love mints for their fragrance and culinary uses, but they can spread aggressively in the garden. Sink a large pot into the ground. Then place the invasive mint in a slightly smaller pot liner. This limits the spread of the roots.Successful Container Gardens Main Navigation Home Welcome to the World of Container Gardening Choosing a Container Selecting Soil Mixes Considering Environmental
The Elements of Successful Container Gardening
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In most ways, planting and maintaining a container garden is the easiest form of gardening. All you need is potting soil, plants, and slow-release fertilizer. But container gardening is slightly different from other forms of gardening, mostly due to the fact that the plant isn’t in the ground where it can stretch out its roots. Understanding five important aspects will ensure you have success with your container gardening.
Drainage Is Critical
Having adequate drainage in a pot may be the single biggest factor determining if plants live or die. In a traditional garden, excess water drains into lower soil layers, but in a container, excess water can be trapped and drown or rot plant roots unless the water can drain through.
Any pots or other containers need holes in the bottom that are sufficient enough to let any excess water drain away. Not all pots sold in stores will provide adequate drainage, especially if there is only one small hole in the bottom. If you buy one of these pots, you’ll need to be careful to avoid waterlogging the soil—especially if the pot is small—or you can add more holes in the pot before using it. On a metal pot, poke holes with a hammer and pointed tools, such as an awl or even a large nail. Or, use a drill to bore a few good-sized holes in the bottom. On a ceramic pot, use a drill with a masonry bit. (Wear safety goggles whenever drilling, of course.)
Generally speaking, the more drainage a pot has, the better. Many more plants are killed by drowning or rot than by under-watering.
The second part of the drainage equation is ensuring that the soil doesn’t drain through the pot with the excess water. Provide a permeable screen or filter material in the bottom of the pot to allow water to pass through but retain soil particles. Any number of materials can be used, such as vinyl window screening, pieces of landscape fabric, coffee filters, paper towels, or sheets of newspaper. The often-used method of putting gravel in the bottom of your pots doesn’t work very well.
It is also a good idea to elevate your pots so that the water isn’t blocked from exiting out of the drainage holes. You can use any number of ways to elevate your plants, but pot feet are the easiest. If you have a heavy pot, wheeled stands can serve double duty—getting a pot off the ground and enabling relocation.
Removing Plants From Nursery Containers
Transplanting plants from their nursery flats into your garden containers is a crucial step, and you’ll be off to a bad start if you don’t use care. Novice gardeners often remove nursery plants from their containers by tugging upward on the stems, which may well kill the plant before you even begin. Better methods include:
- On plastic six-packs or four-packs, hold the plant close to the soil line with your thumb and finger of one hand, and then use the other hand to squeeze the plant out of the cell by pinching the pot.
- If the plant is in a nursery pot, you might be able to push the plant up from the bottom. If the plant is root-bound, with roots even coming through the bottom of the pot, you may need to tear or cut off the protruding roots. Then score around the inside edge of the pot to loosen them.
- Larger nursery plants can be removed by turning the pot upside down while supporting the base of the plant at the soil line with one hand, then tapping on the bottom of the pot with the other. This force should loosen the root ball and cause it to slide out onto your supporting hand.
If the plant’s roots are dense and encircling its soil tightly when you remove the plant from its nursery container, cut or tear the roots aggressively before planting. This will allow them to grow freely outward, rather than in a circular pattern that can strangle the plant.
Fertilize Before Planting
Container plants can be prone to slow starvation because frequent watering causes nutrients to drain out of the potting soil. The easiest way to remedy this is to mix a slow-release fertilizer into the potting soil before planting the container. Many types of slow-release and time-release fertilizers are available, but a standard granular all-purpose organic fertilizer is a good option.
The two main things to know when planting a plant in a container (or anywhere else, for that matter) concern its roots, in the depth of planting and having optimum soil contact with roots:
- Break up dirt clods in the pot to ensure removal of potential air pockets around roots. You want the plant’s roots to be thoroughly in contact with soil. In a crowded pot it may be difficult to avoid air pockets between plants, but be forceful about this, because air pockets cause a plant’s roots to dry out and thus retard their growth. A thorough watering immediately after planting helps settle the soil. After watering, fill in any holes or depressions with extra potting soil.
- Situate the plant in the container at the same level as it resided in its nursery pot. The plant’s stem should be covered to exactly the same level as it was. (Though if you have a small tomato, you should cover more of the stem, as any part of the stem in contact with the soil will sprout roots, making for a stronger plant.)
Water and Feed Correctly
Watering a container garden is more art than science. Although plants vary in their water needs, when planted in containers, plants may dry out much faster than those planted in the ground—especially if they receive a lot of hot sun, are in black pots, or their containers sit on a hard surface, such as concrete or asphalt. Most plants like to be kept in soil that is moist and damp, though not wet. You may find that you need to water every day. To test soil dryness, stick your finger into the soil up to the second knuckle. If your fingertip feels dry, it’s time to water.
Water slowly and check that the water is soaking straight down to the plant’s roots, rather than draining down the crevice along the edges of the pot. Water deeply, until you see the water begin to drain out of the bottom of the container.
After planting, feed the container plants with a diluted liquid fertilizer every one to two weeks during the growing season. Container gardens need more regular feeding than plants in an in-ground garden because container plants’ access to food is limited by the amount of soil in their pots and the washing away of nutrients by the frequent watering.Container gardening is easy, but it does require some adapted techniques for transplanting, fertilizing, planting, and watering. ]]>