Growing plants in containers lets you have a garden even when the space for one is limited or nonexistent. You can install a planter box below a window or use containers to turn a tiny balcony or patio into a leafy haven.
Gardeners with plenty of room appreciate containers, too, valuing the versatility they offer.
Blooming container plants bring seasonal color to garden beds, a porch, or the front steps and are easily replaced with new ones when their flowers fade.
In addition, containers give you the chance to experiment with new plant combinations and with plants not suited to the native conditions.
For instance, if your soil is alkaline or clay-like but you are longing to raise acid-loving plants or those that demand fast drainage, just fill the pots with the sort of soil they need.
Plants too tender for your winters can be moved to shelter when cold weather hits.
Choose containers with at least one drainage hole, so water won’t accumulate around your plant roots. Submerge terra-cotta pots in clean water and let them soak thoroughly. If the pots are too dry, they can initially draw water away from the potting soil. Scrub used containers with a solution of 1 part household bleach to 9 parts hot water.
A good potting soil allows roots to grow easily. It should be fast draining, yet moisture retentive. Quick drainage means roots won’t run the risk of suffocating in soggy soil, while good water retention saves you from having to water too often.
Regular garden soil, even good loam, is too dense for container use. For best success, most gardeners turn to packaged potting mixes, which don’t contain soil.
They’re soil-less mixtures of organic materials (such as ground bark, sphagnum peat moss, and/or compost) plus mineral matter such as perlite, pumice, or sand. Limestone may be added to balance the acidity of peat moss. Fertilizers and wetting agents (soil polymers) may also be included.
Before planting, flush the mix with water once or twice to eliminate excess salts.
Because containers have only a limited area from which to draw moisture, these plants must be watered more often than those grown in the ground.
In hot or windy weather, some (especially those in hanging baskets) may need watering several times a day. In cool weather, it may be sufficient to water less often.
Test the soil with your finger. If the soil is dry beneath the surface, it’s time to water.
Apply water over the entire soil surface until it flows from the pot’s drainage holes. This moistens the entire soil mass and prevents any potentially harmful salts from accumulating in the mix.
If the water drains out too fast, (virtually the instant you pour it in), there’s probably air space between the soil and the container walls. In this case, completely submerge the container in a tub of water for about half an hour. For larger pots, set a hose on the soil surface near the plant’s base and let water trickle slowly onto the soil.
A drip irrigation system can make watering almost effortless. Kits designed for these purposes are widely available.
Container plants need regular feeding, because the frequent watering leaches nutrients from the potting mix. Hydrate the plants before applying fertilizer.
If plants are dry and then fertilized, burning can occur due to too much fertilizer being absorbed. Water lightly first before fertilizing.
If using a granulated (dry) fertilizer, water lightly before and after application and follow up the next morning with another light watering.
If using a liquid or water soluble fertilizer, water at base of plant and not on foliage. Do this in the early morning or evening instead of the hottest part of the day.
Apply a liquid fertilizer every 2 weeks during the growing season, following directions on the label. Also, you can mix a controlled release type fertilizer into the potting mix before planting.
If roots are crowded and protruding from the drainage holes, the plant has outgrown its container and needs a roomier home. Because you want to keep the soil mass fairly well filled with roots, it’s best to shift the plant to a slightly larger container rather than a much bigger one.
If the pot is too large, the ration of soil to roots will be too great for the roots to absorb all the moisture after watering, a situation that often leads to root rot. Select a new container that allows just an inch or two of fresh mix on all sides of the root mass.
If the root ball is compacted (with tightly wound roots), make four shallow vertical cuts down its sides with a sharp knife to encourage the roots to move out into the new soil.
If you want to keep an older plant in the same large pot indefinitely, you can root-prune the plant periodically. Gently turn it out of its container and use a sharp knife to shave off an inch or two from all four sides and the bottom of the root ball.
Place fresh potting mix in the bottom of the container, replace the plant, and add fresh mix around the sides. Water thoroughly and fertilize with the above mentioned recommendations.
This summer many people are planting vegetables in containers as they lend themselves well to this type of gardening. With some thought to selecting bush or dwarf varieties, almost any vegetable can be adapted to growing in pots.
Vegetables that take little space such as carrots, peppers, radishes, lettuce, or crops that bear fruits over a long period of time, are perfect for containers.
Seed companies have seeds on the market made for containers, including cucumbers, round eggplants and round carrots.
There are blueberry varieties that do well in containers and are easy to grow. Citrus do well in container, too.
There are so many choices of plants that will work in containers you can start filling in your garden today.
If you have questions about container gardening, ask a Master Gardener. We are at the farmers markets, libraries, and other advertised events.
We have a hotline, 784-1322, where you can leave a detailed message and we will return your call. Send us an e-mail at firstname.lastname@example.org.
We’re here to assist you with your gardening questions.
Sharon Rico is a Master Gardener with the University of California Cooperative Extension office in Fairfield. If you have gardening questions, you can call the Master Gardeners office at 784-1322.