Labor easily takes top billing in most conversation concerning berry production today. While this is a very big deal for us, what does it look like outside of this industry?

A lot of the same actually.

Trucking: In spite of rising demand for freight shipment in our strengthening domestic economy, trucking businesses are hurting for drivers. Under the heading “Who's driving?” the August 28 trucking industry analysis by ValueLine, a leading stock advisory service, describes that a “worsening driver shortage is the biggest news affecting the industry today”. Truck fleets will have to either lower driver standards, raise pay or consolidate with other companies to purchase access to more drivers.

Housing: Likewise to trucking, what should come under the heading “Who's building?”, the September 21 quarterly earnings call of Lennar Corporation, one of the largest builders of single and multi-family homes in the US, alluded to labor as “having become a limiting factor” in being able to build houses. This has to be really frustrating, because the prospects for builders right now are really good – employment is up, demand is strong and consistent and Millennials, long understood to be on the sidelines of the market, are starting to form households. Nevertheless, according to the call, the entire labor market has tightened and rapid growth in the housing market will be limited by available labor.

So, are the worker shortages we face in the berry industry simply a reflection of a larger, secular shift in the labor situation in the USA? Given the above examples, one could say maybe so.

So the question now is, so what Mark, we're around 68 chill units accumulated as of September 22 in Macdoel, but what does that actually mean to me as a grower?  How does it compare to years past?

Fortunately, we can reference past year's chill accumulation and make just that comparison.

Again, this year up to September 23 (I'm adding in last night's numbers right now), we have 32 hours below 32^o F (0.0 chill units/hour x 32 hours), 153 hours between 33^o F and 45^o F (153 hours 1.0 chill units/hour), 170 hours between 46^o F and 60^o F (170 hours x 0.5 chill units/hour), and 188 hours over 61^o F (140 from 61^o F to 80^o F and another 48 over 81^o F).  Negative chill units will be from the 188 hour (which we multiply by a quarter to obtain an approximate range for temperatures from 61^o F and 65^o F), which gives us (188 x 0.25) 47 multiplied by -0.5 chill units/hour = -24 plus the balance of 141 multiplied by -1 chill units per hour = -141.  Adding -141 + -24 + 153 + 85= + 73 chill units accumulated so far.

Looking at the numbers for 2014, which we consider a pretty hot fall in Macdoel, the same calculations as above from 3 below 32^o F, 137 hours between 33^o F and 45^o F, 147 hours between 46^o F and 60^o F, and 256 hours over 61^o F (202 from 61^o F to 80^o F and another 54 over 81^o F) brings us to -13 chill units accumulated by September 23.   This squares with observations from the field in September 2014 that the plants were barely chilled at all.

Next, let's have a look at 2013, which has been described to me as a "normal" chill year.  Referring to the Lassen historical chill chart, by September 23, we experienced 10 hours below 32^o F, 127 hours between 33^o F and 45^o F, 208 hours between 46^o F and 60^o F, and 226 hours over 61^o F (181 from 61^o F to 80^o F and another 45 over 81^o F) which by using my calculations brings us to +34 chill units accumulated by September 23, 2013.

Conclusion; from the looks of it we are tracking right along and having a normal accumulation of chill in the autumn of 2015.

XX

Strawberries (and caneberries) rely on enough accumulation of chill to develop normally. Insufficient chill in strawberry results in lower vigor and productivity, while excessive chill can result in overly vegetative plants with again lowered productivity. This is an expansive topic, and readers can refer to other articles in this blog to familiarize themselves with the concept further.

The question we take up today is with the current spate of warm temperatures during the day in the strawberry plant production areas in Northern California, are we losing some of the accumulated chill during the night. The answer is an unequivocal “yes”.

Consider the chart below taken from the UC Davis Fruits and Nuts website which comes from the publication “Chilling Accumulation: Its Importance and Estimation” by David H. Byrne and Terry Bacon out of the Department of Horticultural Sciences at Texas A&M University:

http://fruitsandnuts.ucdavis.edu/Weather_Services/

chilling_accumulation_models/about_chilling_units/

Let's go to the accumulator of chill hours from Lassen Canyon Nursery to apply this to our situation today:

http://lassencanyonnursery.com/macdoel-ranch-cumulative-chilling-hours/

As of 9/22/2015, it looks like we have 32 hours (or units) below 32^o F (0.0 chill units x 32 accumulated), 143 hours between 33^o F and 45^o F, 166 hours between 46^o F and 60^o F, and 177 hours over 61^o F (130 from 61^o F to 80^o F and another 47 over 81^o F). I'm assuming the interesting part of chill accumulation for Lassen is the 33^o F to 45^o F range, which we'll multiply by 1 for 143 chill units, then add on the less effective 46^o F and 60^o F of 83 chill units (166 hours x 0.5) for a total of 223 accumulated hours in Macdoel so far.

However, from this total of 223 hours accumulated we are going account for the negative effect of 177 hours over 61^o F. We don't have the advantage of knowing how many hours were in the range of 60^o F to 65^o F for which the multiplier is only -0.5 chill units, but indulge me and let's put that amount at a quarter of the 177 hours over 61^o F (177*0.25 = 44) . Meaning that (44 hours x -0.5 chill units) + (133 x -1.0 chill units) = -155 chill units.

As such, according to the Utah Model, total accumulation this year as of September 23 in Macdoel is 68 chill units (223 units - 155 units).

‘Grenada' is the third of the 3 short day strawberry cultivars released by former UC plant breeders Doug Shaw and Kirk Larsen in 2014. ‘Grenada' produces a substantial amount of fruit early, with an average of 42% of the total yield being produced in the early part of the season, meaning up to May 1 in Watsonville and up to April 1 in Irvine. The fruit is large (bigger than that of ‘Ventana') and of excellent flavor.

Owing to the above exceptional productivity of early fruit, ‘Grenada' is a plant of small size early in the season.

Growers should take care to understand the disease resistance profile of ‘Grenada', which is similar to ‘Fronteras' and ‘Petaluma' in resistance to Macrophomina but is more susceptible to Fusarium wilt. Resistance to Verticillium is similar to that of ‘Ventana', and Phytophthora resistance in line with that of ‘Petaluma' and ‘Fronteras'.