Must-Know Tips for Growing Potted Plants, Indoors or Out in Your Garden
Giving your plants the right soil, water, light, and fertilizer is important, no matter where they're growing, but container-grown plants usually need a little more attention than the ones that grow in the ground. One of the best parts of growing potted plants is that you don't necessarily have to worry about them surviving the winter; you can bring your favorites inside when the temperature starts to drop, or you can grow them exclusively as houseplants. If you're going to grow multiple plants in one container, keep in mind that they'll need to have similar sun, water, and soil requirements in order to thrive.
Best Soil for Potted Plants
Container plants should be grown in a special potting mix that doesn't contain soil. Garden soil is too heavy and can compact roots, cutting off their oxygen. It also often contains weed seeds. Instead, buy or make a soilless mix; look for one composed of coconut fiber (coir) or peat moss, vermiculite or perlite, and other ingredients. A lightweight soil for potted plants needs to provide good drainage, hold moisture, and give roots room to grow.
Test Garden Tip: Most orchids are the exception to this rule. They need a potting medium that gives even better air circulation than the typical soilless mix. Bark chunks or moss are used for potting some orchids, while other types only need a slatted wooden basket or a slab of wood.
How to Water Potted Plants
Water and good drainage play a key role in thriving container plants. Overwatering tends to kill more potted plants than anything else, so as a general rule, try to water less often and more deeply, rather than giving your plants light, frequent waterings.
One easy rule: Use room-temperature water when possible. Cold water can harm roots and foliage, and hot water can kill plants instantly. Also, allow tap water to sit for several hours to evaporate any dissolved chemicals. Softened water contains sodium that can accumulate in the soil and burn plant roots when used over time. Use an outdoor tap for plant water, or install a tap for watering plants before the point where the line enters the softener.
Watering plants in the morning allows any moisture on the foliage to evaporate before evening; foliage that remains cool and wet during evening and nighttime hours is more likely to develop a disease. This tip is especially crucial for certain disease-prone plants like tomatoes and roses.
Another must: Containers need drainage holes so plants aren't left sitting in water. You can place saucers under pots to catch and hold rain or extra water, but remove any excess water left after about an hour to prevent root rot and excessive sogginess in the soil.
Before watering, always check soil moisture by poking your finger into the soil. Only water if the soil feels dry. Wet soil can be tricky, because when roots drown and die, the overwatered plant often droops, making you think it needs more water. Checking the soil moisture prevents you from making the problem worse with even more water.
If a plant has dried out completely, submerge the pot in water to its rim to allow the soil to soak up moisture from the top and the bottom. Submerging is usually an easy way to water dried-out hanging plants as well; use a tub or sink, and leave the pot there until air bubbles have stopped appearing.
How often you need to water depends on the type of plant, the size of the pot, the weather, and other factors. Outdoor containers might need watering as often as once or twice a day during hot, dry weather but much less during cooler, cloudy conditions. As a general rule, the larger the container for your potted plants, the less watering you'll need to do. The container material matters, too: A plant in a porous clay pot needs water more frequently than one in a plastic or ceramic pot.
Various types of plants have different watering requirements: Cacti prefer infrequent watering, while cannas like constantly moist soil. In general, plants with a lot of leaf surface or soft, lush foliage are thirstier than those with less foliage or waxy leaves. Plants with silver, fuzzy leaves also typically need less water.
Best Containers to Use for Potted Plants
Outdoor containers, in general, should be at least 12 inches wide and 10 inches deep. The bigger the pot, the more room there is for roots and the better your plants will perform. Large potted plants need larger containers, and small ones should go into smaller containers. Mixed containers often look best when you use a large container and include graduated heights and variety in foliage texture.
Light Requirements for Potted Plants
All plants depend on light for their survival, and making sure your potted plants get the right amount of light is crucial to keeping them happy. For both indoor and outdoor containers, group plants with similar light requirements. Don't mix shade lovers with sun lovers in a single pot; one or both of them will be unhappy, depending on where you place the pot.
How to Fertilize Potted Plants
Every time you water a potted plant, nutrients leak out of the drain holes along with the excess water. An easy way to add nutrients back into the soil is to use time-release organic fertilizers. Soil microbes activate organic fertilizers, which slowly release their nutrients to plants.
Compost improves soil drainage and adds nitrogen (which plants need for healthy foliage) and other nutrients. Other sources of nitrogen include blood meal, cottonseed meal, fish meal, and fish emulsion. Buy bags of premixed, balanced (the numbers on the bag should match, such as 10-10-10) organic fertilizer and use it in addition to organic amendments to build healthy soil for your pots. Follow label directions for amounts to use in containers. Feed when you plant, then monthly after that.