Strawberry pots can be a great way to grow strawberries, herbs and small annual flowering plants, said Jeff Rugg, a University of Illinois Extension horticulture unit educator.
"A strawberry pot is a flower pot usually less than two feet tall that has a series of holes around the sides where additional plants are grown," said Rugg. "They can be made from clay pottery, ceramic pottery, plastic and even wood."
Strawberries are not the only plants that can be grown in these pots. They allow several plants to be planted in a very small area. They often have six to eight holes, so you can plant six different kinds of herbs in one small spot. They can be placed on a patio or balcony, so anyone can grow herbs and strawberries just about anywhere. If you fill the pot with new sterile soil, you won't have any weeding to do and the plant's roots will have fewer disease problems.
"Strawberries are often planted in these pots because they are small plants with a shallow root system, so each plant doesn't compete with the others for water," he said. "The fruit will often turn out better as well, since they are not growing on the ground where they are susceptible to bacterial and fungal disease problems. Strawberries can be planted in the pots in areas of the country that can't grow them successfully in the ground. Usually, the plants are replaced each spring."
All it takes to plant one of these layered pots is to cover the bottom hole with a piece of screen, cloth or anything that will let the water out, but not the soil. "Never add a layer of gravel in the bottom of the pot," Rugg cautioned. "It does not increase drainage. In fact, it slows the drainage in the bottom layer of soil.
"Fill the pot to the bottom of the first set of side holes, poke the roots in the hole and spread them on the soil, then add more soil up to the next holes and repeat until you can plant a few in the top. You can add some crumpled up newspaper or sphagnum moss around the plants to keep the soil from washing out of the hole. When you replace the plants, you should replace at least half the soil, if not all of it."
To make it easier to water every plant in the pot without over watering the top plants and under watering the bottom ones, you can insert a pipe in the pot before adding the soil. You can use any type of pipe and all you do is drill holes in it to have water seep out at all levels.
"If you have a very large strawberry pot, you could set a plastic milk jug in the bottom of the pot," he said. "Poke holes in the jug and holes in the pipe that rises to the top of the strawberry pot. Water the pot by filling the milk jug via the pipe. This will allow for a longer soaking of the bottom level plants, without over watering them. Test the jug before placing it in the pot to see if it slowly drips.
"You can also use drip irrigation lines running through the center of the pot with an outlet at each plant.'
Large strawberry pots filled with wet soil can weigh a lot. It is best to fill and water them where they will be left for the summer. If you use new sterile soil, it will probably have fertilizer in it, but additional slow release fertilizer will be beneficial during the summer.
Normal strawberry plants will only produce fruit in the spring, but ever bearing, day-neutral plants should give you fruit most of the summer. They are called day-neutral since the length of daylight does not affect their flowering. Sometimes, they are called ever-bearing and they make the best varieties for strawberry pots. Tillicum, Ozark Beauty, and Quinalult are good ever-bearing varieties.
"It takes about four plants per person to keep enough berries coming, so you may need more than one pot," he said. "If the pot is in a cool protected location over the winter, so that the plants and soil in the pot don't dry out, the strawberry plants could last several years before you would need to replace them."
"If you live in a climate that freezes during the winter, you can bring the pot indoors," Rugg noted. "Strawberries are better off going dormant in the cold, but the pot may freeze and crack, unless it is the plastic kind. Many of the herbs can be grown indoors over the winter in the pot, so in the fall take out the strawberries, replant with herbs and bring the pot inside."
"I use a modern version of the strawberry pot called a 'Stack A Pot.' It is a series of trays that each holds three plants," he said. "They can be stacked to create a column and they come in a variety of diameters. There are versions that can stack on a deck railing and others that can hang.
"They have several advantages over the old style pot. I can take off a tray and easily reach the soil and plants on that layer to replace them and then I can change the order of the stacks. They have an overflow between layers and a water holding area in each tray. I water the top layer and once it is full, the water moves down a layer until all the trays are full." Check your local nursery for the pots when you are buying the strawberries, he added.