Introduction:  As the planting season for strawberry approaches, it is useful to review some concepts of strawberry plants and planting. Strawberry growers occasionally have questions about the size of strawberry transplants (i.e. crown size) and its effect on plant growth and yield. 

The following is a summary of a study run over two years as an investigation of whether strawberry crown size had any effect on strawberry fruit yield and size.

For those who want to see the full report, it starts on page 5 of the Monterey Crop Notes for November/ December 2007.

 http://ucanr.org/cropnotestransplant2007

Materials and Methods: 

Treatments:  The trials were conducted in a well managed organic farm in Moss Landing, CA.  In year one, the study consisted of treatments of “large” and “small” size transplants.  Measurements were done with a caliper at the middle of the crown. The following varieties were tested at the sizes given below:

Seascape: small < 1.1 cm, large > 1.2 cm
Transplants were dug 10/27/04 in Macdoel, and planted 11/16/04.

Aromas:  small < 1.1 cm, large > 1.3 cm
Transplants were dug 10/26/04 in Macdoel, and planted 11/9/04.

In year two, the study included a third treatment, consisting of “slicks” (known as “lisas” in Spanish) for the varieties of Seascape and Albion.  “Slicks” are very small crowns which are almost entirely made up of primary roots and no secondary roots, giving them a smooth appearance (see photo accompanying this article).

Seascape:   “slicks”, < 1.1 cm, large > 1.2 cm
Albion:  “slicks”, small < 0.9 cm, large > 1.1 cm
Both Seascape and Albion transplants were harvested in MacDoel 10/25/05, and planted 11/22/05

It should be noted that the large crowns in each treatment were not a common feature.  In each box of 1000 crowns large crowns represented probably 5-10% of the total numbers of plants.

Plants were measured for plant diameter early in the season, possibly on a monthly basis.  Fruit yield, both count and weight of fruit from each replicate plot, were evaluated by harvest by qualified personnel harvesting on a regular schedule. 

Results:  In the first year trial, plants of treatments planted to small crown sizes had smaller diameters than larger crowns one and a half months after transplant.  Three months after transplant this difference had disappeared.  There were no significant differences in plant diameters at any date in any size categories for the varieties tested in year 2.

Fruit production was significantly lower in smaller crowns of Aromas in the summer months of year 1, and resulted in lower total fruit production.  There were no differences in fruit production in year 1 or year 2 for Seascape.

For Albion, fruit production for "slicks" and small crowns was significantly lower than large crowns in the months of June and July, but there were no differences in total yield between any size class.

With very little exception did fruit size vary significantly between any of the crown size treatments by month or through the season.

Discussion:  Although there was some variation by month for certain varieties, transplant crown size was not a good predictor of total strawberry fruit productivity in this study.   What this means is that, while there was some cyclicality in production for some varieties, size of the strawberry transplant did not have an effect on total fruit yield.