Container Gardening

Growing plants in containers is a great option for anyone limited by space, mobility or soil conditions. Containers also can provide a nice accent near porches, windows or doorways that can be relocated or changed seasonally, if desired. Blooming annual plants and textured leaves provide an attractive display that is reasonably easy to care for, even by a beginning gardener. A few herbs make the perfect addition to a kitchen window box, always near and ready for a last-minute addition to a favorite recipe.

Container Selection

The container options for your project are nearly endless – just avoid anything that might be toxic, such as plastic that once contained oil or other chemicals. Wood, terracotta, plastic and metal can all be acceptable. Pots, planters and hanging baskets are most common, but watering cans, wheelbarrows, urns and hollowed-out stumps also will work. Wire baskets can be lined with moss or coconut coir to support soil and add visual appeal. One of the most important considerations when choosing a container is to select one with a depth that will allow enough soil volume to accommodate the roots of all the plants when mature. Adequate drainage is essential; holes can be drilled into the bottom of containers, if needed.

Planting

Garden soil for pots is never a good choice. Often, it has a high clay content, which can compact and restrict oxygen availability to the growing roots as well as trap water, increasing the chance of rot and disease. Purchasing a quality potting mix will ensure that it is lightweight, loose and disease-free. It will usually contain vermiculite and perlite to aid in aeration and moisture retention. It also may contain organic matter, such as peat or compost.

Plant seeds to a depth that is twice the diameter of the seed. If planting transplants, purchase only healthy plants from a quality source and handle carefully. Loosen roots slightly and plant to the depth they were planted in the tray. Tomatoes are the exception – they can be planted to the first set of leaves as they will make roots up the stem. Plant after the danger of spring frost has passed for your area if the plant you are planting isn’t cold hardy. Check the WVU Extension Garden Calendar for planting dates for your region and planting time for vegetable crops.

Plants in containers are growing in various growth mediums and may have higher fertilizer needs, depending on the type of fertilizer used. It might be adequate to add slow-release fertilizer once a year. If the liquid fertilizer is the preferred choice, it will be necessary to add fertilizer every three weeks or so. It is important to remember that the potential for salt build up in containers is very high. Good practice is to “leach-out” the salts by rinsing out the soil. This is done by placing the hose over the pot and let the water run through until the water that comes out of the pot is clear. Leaching out the salts should be done once a year.

Watering

Water is one of the most important considerations for container gardens. Plants in containers dry out faster than those grown in-ground. Check plants often to determine their water needs. During hot, dry spells in sunny locations, potted plants will likely need to be watered daily or possibly even twice a day. The best method is to feel the soil to see if it is dry or damp and water as needed, watering until water runs out of drainage holes to endure moisture reaches the lower areas of the container. It is important to ensure drainage holes are not blocked; waterlogging can cause root rot. Self-watering containers are available and plans to build homemade versions can be found on the internet.

Light and Temperature Requirements

All plants in a container should be suited to the location of the container or planter. Most plants need six to eight hours of sunlight a day, but vegetables prefer at least 10. If the location for the container garden will be in the shade, be sure to select plants that can tolerate it.

Many gardeners enjoy tropical plants that are not suited to West Virginia’s climate in cooler seasons. If you choose to grow tropical plants, the planters need to be portable to be brought inside in cooler months; heavy planters can be placed on a dolly with casters to move them around, as needed. Additionally, keep potted plants away from walls and off of driveways and stone or cement patios – they may get scalded and overheated from the heat that reflects off these surfaces during hot months.

Acclimation

Whenever moving plants from one environment to another, it is essential to transition or acclimate them slowly. This is true whether you are taking new transplants from a temperature-controlled greenhouse into your garden or transitioning a tropical plant from your home into the outdoors, where temperatures may fluctuate vastly from day to night.

Indoor Plants

Plants grown indoors provide beauty and a calming environment, as well as releasing oxygen and decreasing pollution. They can provide color, texture and scent to any room. Indoor settings typically provide uniform temperature and humidity, but some indoor spaces may not have the ideal light conditions for a plant to thrive. The light intensity (brightness of the light), the light quality (spectrum or colors of the light received) and duration (time in light) are all important and needs vary by plant. Additionally, some tropical-type plants may prefer a more humid environment, and all container plants need checked daily to ensure the soil is adequately watered. Humidity can be increased with humidifiers or by adding containers of water near a heat source, such as a radiator. There also are plants that prefer a drier environment, such as cacti and succulents.

Herbs in Containers

Most herbs do well when grown in containers either outdoors or indoors. Herbs can be grown for their culinary uses or appealing fragrance.  Annual herbs need to be replanted yearly, while perennials can be maintained without replanting. Some tender herbs, such as rosemary and thyme, struggle with cold weather and may need to be planted annually if they aren’t grown indoors. Once a plant is mature, pieces may be snipped off, as needed. To keep the plant healthy and productive, do not trim more than one-third of the plant, as it needs leaf area for photosynthesis. Harvested herbs can easily be dried or frozen for later use.

Vegetables in Containers

Many vegetables can be grown in containers with the same consideration as other plants. Stakes cages or trellises can be added for plants that have vines or fruit that need to be supported. Quick maturing vegetables, such as radishes, green onions and leaf lettuce, can be harvested often and replanted for multiple crops. Large containers can contain a mixture of vegetables, if desired, so long as the plants have similar light and water requirements. Many vegetables, such as potatoes, can be grown in buckets with combinations of soil and straw or directly in straw bales. Light requirements, container size to accommodate the roots of mature plants and water needed are some of the major considerations.

References

Recommended Varieties: 2015 Vegetable Production Guide (2015). Vegetable Varieties Recommended for West Virginia. Dr. Lewis Jett, WVU Extension Commercial Horticulture Specialist

Minimum Container Size Needed for Vegetables: (2018). Plants Grown in Containers. North Carolina Extension Master Gardner Handbook

Author: Jodi Richmond, WVU Extension Agent – Mercer County

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