Editor’s Note: This is the first in a three part series on container gardening.
Containers are great for people with limited mobility, as well as people living in apartments or with limited space in a yard. But another option is to bring in plants during the winter, especially herbs and vegetables that can be harvested and eaten.
If you have a sunny window, sheltered balcony, or patio, you can have fruits, vegetables, herbs, and flowers. Annual plants and veggies look great in containers, and you don’t have to worry about hardiness zones when you grow them indoors. Containers of flowers look best with spillers (a vine or trailing plant), fillers (the middle tier), and thrillers (usually the tallest and most dramatic plant).
Growing in containers requires some special instructions. Here are some tips on how best to grow in containers:
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Use an all-purpose potting mix that contains a mix of ingredients like peat, vermiculite, perlite, sand, and bark. There are special blends like extra sandy for succulents or an organic compost-infused blend for edibles. Or enhance a light peat-based mix with compost and polymer crystals to make it more moisture-retaining for window boxes, hanging baskets, and other containers that dry out quickly.
Renew the soil annually with fresh potting soil plus a dose of slow-release fertilizer.
Plant
Before planting, place a heavy container in the desired location.
If using a terracotta pot, soak it in water first. If the pot’s drainage hole is large, cover it with a colander, newspaper, or a coffee filter to prevent soil from spilling out. If a container doesn’t have a drainage hole, it’s best to poke a hole or two in the bottom if possible. It is then necessary to place a tray under the pot to ensure water is visible to ensure the roots have adequate moisture. If your containers don’t have holes, you can also accidentally drown the plant.
It’s best to put a coffee filter or hardware cloth to cover the hole so no dirt comes out at the bottom. Fill the container three quarters full; Mix in slow-release fertilizer and water-retaining crystals, then top up with regular potting soil. Arrange the plants in their original containers in the pot, starting with the largest or tallest and ending with the smallest. Place the tallest plant in the center for a symmetrical design, or to the side for an asymmetrical balance. Rearrange the plants until you are happy with the arrangement.
Just before planting, dip the root ball of each plant in a solution of water and root stimulant formulated for transplants. Take the largest plant out of its nursery pot and place it in the container, adding potting soil around the root ball. Put the smaller plants in place. Top up with soil mix between plants without packing them.
If you want to plant seeds, sow them directly and follow the instructions on the package. Leave 2 inches between the top of the soil mix and the container for the water and mulch. After planting, continuously moisten the potting soil (until the water runs out of the pot’s drainage hole). Place the plants in the shade for a few days to allow them to recover from transplanting before moving to their final location.
irrigation
Containers usually need to be watered daily during the summer, or every two or three days during cooler periods, unless it rains. Hot, dry weather and small pots may require twice daily watering. Plants suffer from too much water as well as from too little. Determine if a container garden needs water by sticking your finger in the soil up to the second knuckle or using a soil moisture meter. When the soil feels dry, it’s time to water. Check the pots daily. Soak the potting soil thoroughly. Excess water should drain from the containers. Soil acidification, root rot and root-killing mineral salts accumulate in a container that drains poorly. If a soilless mix dries out completely, re-wet it by placing the pot in a large vessel of water overnight.
It is best to water early in the day. It allows plants to take in what they need before the afternoon heat causes excessive evaporation. Watering in the evening can leave moisture on the leaves and encourage disease. Use a watering can for watering if you only have a few containers; Use a drip irrigation set on a timer if you have more than a few containers. That takes the work out of the casting. A drip system also conserves water by releasing it near the plants’ root zones with as little evaporation and runoff as possible.
Check the system regularly, especially in hard water areas, to ensure the timer is working and the lines are not clogged or punctured. Self-watering pots have a built-in reservoir that releases moisture into the soil. They need to be watered less often. Water-retaining mats fit into the bottom of hanging baskets and other containers and wick moisture into the soil.
• If you have any gardening questions, just call 509-574-1604 or email gardener@co.yakima.wa.us and ask a master gardener.
