Sweetcrisp and Springhigh Chill Requirements

[bahamadan]

Hello all,

I'm feeling a bit miffed as a few months ago my local nursery started stocking both sweetcrisp and springhigh blueberries which seems a bit deceiving to me as I thought both required a couple hundred hours chill and we get absolutely none at all, lucky to get below the 60s in winter.

Has anyone grown these in lower chill areas? Would I be wasting my time if I bought one? I know people are going mad over Sweetcrisp.

[Blueboy1977]

Springhigh has very low chill requirements. He exact number I can't quote but it could probably be grown in an evergreen envoironment. Sweetcrisp is listed at 300 chill hours but these numbers are really just an educated guess and are just an approximation. I've had no problems fruiting either one the past 5 years and I know a couple years ago we barely reached 225 chill hours. Best bet is to buy one of each and give them a couple years to see what happens.

In my experience with spring high it seems to be a very shallow rooted variety and probably will be sensitive to root rot. I grew mine for 2 years in a 10 gallon pot and the roots would not grow more than halfway down the pot. I found this out when up potting to a 30 gallon pot. I went ahead and did it anyway. This pot stays very heavy so that tells me the roots are still very shallow. Another sign of this is when I fertilize, this plant stops responding way before all my other varieties as the fertilizer moves past the root zone rather quickly so I fertilize this plant more often than the others with lighter doses. Also spring high tends to be very lanky in growth with really thin stems/branches and gets a lot of fruit knocked off during med to high winds.

[Inkfin]

Spring High I have are only less than a year old and I can not comment on them this early but literatures report Spring High requires 300 chill hours and are resistant to Phytophthora root rot, stem blight, and cane canker, above average resistant to fungal leaf spots.

[Gina]

I don't know about Springhigh - my plants are still very young. (Thanks for the info about them, BB) But I've been growing Sweetcrisps a couple years, and they do bear here in my zero chill area. (We will commonly get into the 40*F, but not often, and rarely into the 30s.) I don't think they bear as much as other areas, but I do get enough fruit to make them worthwhile. In part, I think that's why I grow so many plants because I don't get the bounty that others living in higher hours get that some of my plants would prefer.

Usually for me, about 300 hours is the cut-off for trying a variety. As BlueBoy said, just get a bunch of varieties and give them a try.

I also think the chill hours are not set in stone. I think when a plant is first introduced, there really hasn't been enough years for them to determine how well they do in many different environments. For example, when Biloxi first came out, it was given something like 3-400 hours (I don't really remember). But after a few years, it was determined that it does better in zero chill areas and grown as an evergreen. For me, Biloxi seems to bloom whenever it wants. It's not my favorite, but it's very good to have fruit in mid-summer. And if they are left on the plant, they really do sweeten up.

I also think chill hour numbers, while helpful to home gardeners, are more for commercial growers. A plant might grow and bear in an area of lower chill than recommended, but a grower wants/needs varieties for his specific area that will give him a reliable crop, since it's his living. Homeowners of course also want reliable crops, but if we grow a variety better suited to more hours, well, maybe our production is lighter, or maybe we get a few years that skip. For us it's a hobby.

I've tried a few varieties with higher hours (more than 300) that just haven't worked here. O'Neal (which for some reason our local nurseries still carry), Star (too erratic production here), Abundance (borderline, but just not good enough for the small crops it gives)

[Sarahkt]

I just bought a 4-pack of starter Springhigh plants from an eBay seller, so I can let you know in a few years how they do in zone 9b/10a. I'd previously bought a 4-pack of Sweetcrisp TC starter plants from the same eBay seller earlier this year and all four are doing well, but still far too small to fruit. Hopefully in two or three years...

[bahamadan]

Thanks for the replies! There's a small but cheap pink guava tree that has my eye [and pocket] right now at another nursery but once I get [some spare cash] a chance I'll revisit the prospect of picking up one of the two. Although Gina and Blueboy the reports of scant bearing and a whimsical root-nature are a bit off-putting lol. Gina, I see you say you are zero chill but also that you get down to 40F commonly? Are not chill hours the number of hours between the temperatures of 32-45 degrees fahrenheit? At least according to Google lol, I wouldn't know. So you get some chill?

Also, does anyone know/can confirm that Springhigh or Sweetcrisp is more or as evergreen (or lower chill) than Sunshine Blue? I have one of those that I'm tossing around the idea of putting in a 15 gallon. Thanks again!

[Gina]

... Gina, I see you say you are zero chill but also that you get down to 40F commonly? Are not chill hours the number of hours between the temperatures of 32-45 degrees fahrenheit? At least according to Google lol, I wouldn't know. So you get some chill?

Yes, that is true, I do get some winter chill some years, and some years not, but in general not very much so I often say 'zero'. But compared to your location, it might be enough to make a difference. We do get into the 40's occasionally, but more likely the high 40s. Though the past couple nights it has been around 43-44 or so. I haven't looked it up lately, but I am not sure in the last 10 years that we have made it up to 100 hours of chill in any year.

Also, does anyone know/can confirm that Springhigh or Sweetcrisp is more or as evergreen (or lower chill) than Sunshine Blue? I have one of those that I'm tossing around the idea of putting in a 15 gallon. Thanks again!

I only grew Sunshine Blue for a couple years. It was no more or less evergreen that all the others I grow. All of mine still have all or most of their leaves and unless there is some sort of unlikely artic blast, I expect them to hold them all winter. There never really is a season for leaf drop here (that I've noticed) - they just sort of lose the old ones along the way.

[bahamadan]

Noted with thanks Gina, our low tonight is 74 so there is a bit of temperature disparity I suppose lol. Hopefully when we drop to the 50s in a couple weeks that will give them not chill but at least some slow down.

[m5allen]

Riddle me this.... How do some varieties bloom for me in the fall.... We obviously don't get any chill hours over the summer. Kind of the same situation as Gina is describing.

[Gina]

Noted with thanks Gina, our low tonight is 74 so there is a bit of temperature disparity I suppose lol. Hopefully when we drop to the 50s in a couple weeks that will give them not chill but at least some slow down.

Have you done a search on growing blueberries in other tropical places such as Hawai'i? There might be some information that might be helpful.

[Gina]

Riddle me this.... How do some varieties bloom for me in the fall.... We obviously don't get any chill hours over the summer. Kind of the same situation as Gina is describing.

There is more at play than just chill hours. I am not sure, but I think chill hours might influence coming out of dormancy, both leaves and flowers. The blueberries that don't do well here because of not enough chill generally are unable to produce enough new leaves in the spring, and I think numbers of flower buds is also affected.

But there is also photoperiod, which is a hormonal response to changing day length. A plant will begin to bloom in spring due to the fact the days are getting longer. But the days in fall are about the same length as those in spring, and so there may be some bloom in some varieties that may be 'slightly confused', or don't have much of a photoperiod response. Manipulating photoperiod/light-dark is the reason greenhouse growers can produce blooming Poinsettias in the middle of winter.

Here is a general Wikipedia article about it: https://en.wikipedia.org/wiki/Photoperiodism

[drew51]

I think some have recessive genes for a 2nd bloom. Sweetheart is touted to have a spring and a fall crop, much like everbearing raspberries. Blueberry cultivars are so mixed up with numerous crosses. I'm not surprised at all with fall flowers. It may be photoperiodism, or a lack of chill or a combination of all three. I get about 1600 chill hours, so no worries there for me. i have never seen fall flowers.