Contain yourself, but not your enthusiasm for growing in pots. It is now time to plant your pots and container gardens.
Some tender plants still need night protection: Plants such as coleus, tomatoes and basil will still suffer from cool nights when the temperature is below 55 degrees, so wait until June to place these heat lovers outdoors. You can pot up these super tender plants now, but move the containers indoors at night. Leave big pots in a wheelbarrow and you can more easily move them into a covered garage or garden shed in the evening.
Hardening off newly planted flowers: Most other annuals such as petunias, geraniums, fuchsias and herbs will survive in pots when planted the last week of April or first week of May, but keep the newly planted containers close to the house such as on a covered porch or patio for at least the first week. This allows the greenhouse grown plants to harden up a bit and adjust to the wind and low night temperatures. Don’t worry about cold nights and hardening off cool season plants such as pansies, alyssum, snapdragons, perennials, or leafy greens and hardy herbs. These tough plants love our weather and are ready to grow in the ground or pots.
Do’s and don’ts of container gardening in Western Washington
▪ Do try any and all plants in a pot. Don’t be afraid to experiment with olive trees, shrubs, vines, roses perennials, clematis and hydrangea.
▪ Do provide drainage in any container unless you are growing swamp plants.
▪ Don’t think a small hole in a large pot is good enough. Make more holes with a drill or enlarge the hole. Water needs to drain freely through the soil in our rainy weather.
▪ Do invest in potting soil. Use lighter soil with added perlite for sedums, roses and herbs. You can add a trowel scoop of compost to the potting soil of moisture loving plants such as rhodies, lobelia, fuchsias, begonias and other moisture loving plants.
▪ Don’t try to use soil from your own garden, and if you reuse potting soil, mix it up so it is not compacted. It is nice to add a bit of compost and fertilizer to previously used potting soil.
▪ Do match the size of the plant to the pot. Trees, shrubs and perennials do best in pots at least 18 inches deep but 3 feet deep is even better.
▪ Don’t fill entire pot with potting soil if plants are annuals or have shallow roots. You can use crushed pots or recycled water bottles to fill the bottom third of large pots to keep them lightweight and free draining. Trees, shrubs and perennials prefer that the entire pot has soil.
▪ Do fertilize potted plants. Heavy feeders like annuals and roses like both a slow release plant food and a liquid plant food. Plants in pots need fertilizer. Put on your glasses and read the label on any plant food so you don’t overfeed or underfeed.
▪ Do learn to water correctly. Feel the soil by poking your finger into the soil. Water when the top two inches is dry. The amount of water needed will change as the plants grow and weather warms.
Important for Western Washington: Don’t let potted plants sit in drainage water — raise your pots up a bit by sliding plastic bottle caps under the pots or, for large containers, use bricks, put gravel under the pot or use pot feet to keep the drainage hole from becoming blocked by the weight of the container.
Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at binettigarden.com.
Noon, May 3: “Long Lived Color — using foliage for color in pots and the landscape to create more color with less care.” Windmill Gardens, 16009 60th St. E., Sumner. $5 fee. 253-863-5843, windmillgarden.com.