How to Make Strawberry Potting Mix
The best potting soil for strawberries doesn't always come straight from a bag; it can also be mixed at home using ingredients commonly found at the garden center. Strawberries (Fragaria x ananassa) are widely grown in home gardens within U.S. Department of Agriculture plant hardiness zones 5a to 9a, where they grow equally well in containers and in the ground, according to North Carolina State University Cooperative Extension Service. Strawberries need moist, nutrient-rich potting soil in to set a good crop of berries. A mix that includes a porous material, a steady source of nutrients and a moisture-retaining ingredient provides the right structure and balance for the plants to thrive in containers.
Things You Will Need
Peat moss or coir
18-18-18 fertilizer or an alternative complete fertilizer
Slow-release fertilizer for acid-loving plants
Creating the Best Potting Mix for Strawberries
The right potting soil mix will virtually eliminate the need for fertilizing potted strawberries throughout the season. Researchers at Penn State Extension tried several variations of growing medium for strawberries and concluded that 2 parts peat moss mixed with 1 part perlite works best. This growing mix requires 18-18-18 or another complete fertilizer added to support the plant's growth since it does not provide much nutrition on its own. Note that coconut coir makes a suitable alternative to peat moss, which is sometimes harvested from non-sustainable sources.
Another alternative soil mixture recommended by The Old Farmer's Almanac is a basic mixture that includes fertilizer. Mix 10 quarts of coconut coir, 5 quarts of perlite, 5 quarts of vermiculite, 5 quarts of compost, 2 cups of fine sand and 2 cups of slow-release fertilizer granules. For strawberries, choose a fertilizer that is specifically formulated for acid-loving plants.
Planting Strawberries in Containers
Creating the best potting soil for strawberries is only one aspect of successfully growing them in containers. It is also important to choose the right variety of strawberries and the right type of container. The University of Minnesota Extension recommends choosing day-neutral strawberry varieties rather than the larger, more vigorous June-bearing varieties because they are grown as annuals and they produce fruit all summer long rather than just for a few weeks early in the season. Day neutral strawberries are also much smaller plants than June-bearing varieties so they are more at home in pots and containers. Some common day neutral strawberry cultivars are Albion (Fragaria x ananassa 'Albion') and 'Portola' (Fragaria x ananassa 'Portola').
The right container for strawberries will have drainage holes at the base and plenty of space for each plant. Day-neutral strawberries grow best when spaced 8 inches apart in pots but will tolerate being planted 6 inches apart if the plants are staggered in a long, narrow container. A round 12-inch-diameter pot will accommodate three day-neutral strawberry plants while a 30-inch-long rectangular container will hold five plants in a row. Moisten the potting soil before potting the strawberry plants. Make sure the roots are evenly spread out in the planting hole and that the plant is upright with the base of the stems flush with the surrounding soil.
Growing Strawberries in Containers
Strawberries need eight to 12 hours of direct sunlight each day to bear a good crop of berries. A south-facing exposure is best but a west-facing location can also work if it is unshaded and bright. Growing strawberries in containers in very hot, dry climates can be tricky because the plants still need direct sun, but harsh, very hot sunlight can cause the soil to dry out too quickly; in this case, some light midday shade is best. Avoid shaded parts of the garden that stay cold and dim during the day, or the plants won't bear fruit.
Water is another key factor in successfully growing strawberries in containers. Most strawberry plants need 1 inch of water each week to keep the roots healthy and hydrated while the fruit forms. Soggy soil can cause rot in strawberries so it is vital to let the soil dry out just beneath the surface between waterings. Water at the base of the plant rather than overhead to prevent mold and mildew.
- North Carolina State University Cooperative Extension Service: Fragaria x ananassa
- Penn State Extension: Growing Raspberries and Strawberries in Containers
- Lassen Canyon Nursery: Growing Strawberries in Your Home Garden
- University of Minnesota Extension: Tips for Growing Strawberries in Containers
- The Old Farmer's Almanac: Make Your Own Potting Soil
- Moisten the soil slightly before using if it became dry during storage.
- This mixture contains a slow-release fertilizer. However, you will need to add additional fertilizer the following year, if you continue growing the strawberries in the same space.
Sasha Degnan is a freelance writer and educator specializing in gardening and horticulture. She has nearly 25 years of experience in the propagation and care of plants.