Blueberries

General Information

Blueberry plants (Vaccinium corymbosum) are perennial, bush-like plants in the family Ericaceae. They prefer acidic, well-draining soils and require nitrogen in the form of ammonium (Strik et al. 2020). There are many different blueberry varieties that produce fruit of varying size and flavor during different times in the season. Different blueberry varieties also require different chill hours, the number of hours under 45°F required for fruit set to occur. Varieties with low chilling requirements are best for the San Diego area because of the climate in the county.

We chose several low-chill varieties to grow in this experiment. The 3 main varieties we are growing are Snowchaser, a very early season variety, Misty, an early season variety, and Star, a mid-season variety, but we are also growing Farthing, Meadowlark, San Joaquin, Jubilee, and Sunshine Blue. We will be collecting fruit yield data and comparing these different varieties and several different treatments. For additional information about each variety see the table below. Click here to see photos of each variety. To see which variety is producing the most fruit, check out our Harvest Tracker.

Blueberry plants used in this project were obtained from Fall Creek Nursery in Lowell, Oregon.

Blueberry Variety Characteristics

Variety	Plant Size	Chilling Level	Ripening Season	Berry Size	Berry Qualities	Primary Use	Other
Snowchaser	Rounded, vigoroso	Low chill	Very early	Medium	Medium blue, firm, good flavor	Fresh, processed	Earliest ripening Southern Highbush (April/May)
Misty	Upright, vigoroso	Low chill	Early	Medium to large	Firm, mild, sweet flavor	Fresh market	Must be pruned heavily, planted as a pollinator
Star	Upright, vigoroso	Low chill	Mid	Medium	Medium blue, sweet, outstanding quality	Fresh, processed	Susceptible to Botrytis grey mold and fruit cracking
Farthing	Compact, rounded	Low chill	Early	Medium to large	Crisp, firm, mild tart flavor	Fresh market	Disease resistance, mechanical harvest candidate
Meadowlark	Upright, vigoroso	Low chill	Very early	Large to very large	Excellent firmness, scar may be large	Fresh	Susceptible to Xylella, ‘Funky Spot’ Virus, and blueberry red ringspot virus
San Joaquin	Upright, vigoroso	Low chill	Mid/late	Very large	Light blue, high yield	Fresh, processed	Mechanical harvest candidate
Jubilee		Low chill	Mid	Medium	Fresh, sweet
Sunshine Blue	Semi-dwarf, evergreen	Low chill	Early	Medium	Richly sweet		Hot pink flowers

Plant Health Management

We are testing two growing substrates: a pre-made acid-loving plant mix and a custom mix of bark, peat moss, and perlite. We are also testing three fertilizers: ammonium sulfate and two other fertilizers made for acid-loving plants.

Pests and Diseases

With their shallow roots, attractive white or pink flowers, blue fruits, and green foliage, blueberry plants are susceptible to multiple different pests and diseases. We are conducting weekly surveys to understand which pests and diseases threaten blueberry production in southern California.

A light brown apple moth larva seen inside a blueberry.

Aphids are a common pest, seen here feeding on new growth of a blueberry plant.

We will also be testing scale-appropriate pest and disease management techniques. Many pest management techniques are tested and developed for large-scale commercial growing operations and are difficult or unreasonable to use on a small scale, so we'll be developing methods that can easily be implemented in small-scale urban settings.

Lady beetles serve as natural predators for pests such as aphids.