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Stressing for heat

CAPCOM

CAPCOM

I have seen some really great looking plants grown hydroponically in the past and I am contemplating making the jump, at least moderately. Some questions have arisen that I am looking for some clarification.
 
Stressing your pepper plants prior to harvest to boost capsaicin content in the pods, at least to the extent I have been been doing it, is done by reducing gradually and significantly their water intake. There may be other ways that I dont know of. I am interested in finding out how anyone who is growing hydroponically induces stress on their plants.
 
 
 
I switched to coco last year. It's hydro-like in that all the nutrients are mixed then watered in. Although many people say to NEVER let coco dry out I've had a few occasions where it was bone dry. Watering after this happened didn't seem to affect the plant in terms of growth. The peppers from these plants were noticeably hotter than the ones constantly watered.

I'd also be interested in other ways that stress could be introduced in a hydro system.

Neil
 
I would never let my plants dry out to stress them, the fruit will get soft.  I always pick the morning after a good watering and always have big firm juicy hot pods to suck on.  Never grown a pepper plants in a hydro system either but reducing water to stress sounds like something more suited for cannabis.  I think healthy happy plants make the best fruit with the highest capsaicin content.
 
Blister said:
I switched to coco last year. It's hydro-like in that all the nutrients are mixed then watered in. Although many people say to NEVER let coco dry out I've had a few occasions where it was bone dry. Watering after this happened didn't seem to affect the plant in terms of growth. The peppers from these plants were noticeably hotter than the ones constantly watered.

I'd also be interested in other ways that stress could be introduced in a hydro system.

Neil
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Similar result, although I did it intentionally and with a soil mixture. Pods developed/ripening indoors were also noticeably less pungent.
 
 
With hydro? I don't know. Depending on method, you could isolate a few and test out different approaches. Hilarious pH swings, perhaps?
 
Pepper Ridge Farm said:
I would never let my plants dry out to stress them, the fruit will get soft.  I always pick the morning after a good watering and always have big firm juicy hot pods to suck on.  Never grown a pepper plants in a hydro system either but reducing water to stress sounds like something more suited for cannabis.  I think healthy happy plants make the best fruit with the highest capsaicin content.
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I have never had fruit get soft doing this as the plant will pull all of its vital resources to the pod to further its complete development. The leaves will wilt and wither away before the fruit is allowed to diminish.
 
Regarding drought to get heat.    
I have noticed this phenomenon, if that be the choice of terminology, especially with jalapenos. A plant that had, put out very hot pods and did so consistently with the exception of directly after a good watering. The pods then continued to get hotter as the moisture content of the plant media reduced. My theory to this is, that when the plant has undergone a long absence of water it begins building up defense of seed (capsaicin) to protect what may be its final output of fruit and the continuance of its kind in the event of a sever life threatening drought. It may or may not be far fetched, but it also makes sense.

Cannabis potency is effected by nutrient intake, growing environment and photo period. and last but definitely not least, the denial of flower fertilization.
 
Pepper Ridge Farm said:
I would never let my plants dry out to stress them, the fruit will get soft.  I always pick the morning after a good watering and always have big firm juicy hot pods to suck on.  Never grown a pepper plants in a hydro system either but reducing water to stress sounds like something more suited for cannabis.  I think healthy happy plants make the best fruit with the highest capsaicin content.
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I've never had the pods go soft with drought stressing them either. Drought stress is a documented and statistically proven method that increases pungency of mild to medium heat peppers. No real increase has been found with extremely hot peppers though.

Neil
 
I was a little surprised by the amount of university research that has gone into the study of growing hot peppers. One paper really spelled it out for me though. Peppers are a crop that contributes to a large portion of the economy for places like Jamaica. Buyers want peppers that are consistent, not ones that vary drastically in heat from one batch to another. This comes down to the question of how can you grow a pepper that maintains it's pungency throughout the various harvests in a single year and, from one year to another? Water stressing is one method that contributes to the overall pungency of mild to medium level peppers.

That said, if you're able to grow peppers that meet your requirements, you've hit the mark and that's all that matters.

Neil
 
Drought (and, perhaps, other forms of) stress might not increase capsaicin content in superhots.

From http://hortsci.ashspublications.org/content/47/9/1204.full
"Capsaicin, dihydrocapsaicin, and total capsaicinoid contents in the drought-stressed plants of low and medium pungent cultivars significantly differed from the controls (Table 5). Capsaicinoid contents were decreased in the high pungent cultivars under drought stress, but this decrease was not significantly different from the control plants. The total capsaicinoid contents in the drought-stressed plants of the low pungent cultivars ranged from 2,850 to 55,350 SHUs, whereas those in the medium pungent cultivars ranged from 54,900 to 81,000 SHUs and in the high pungent cultivars ranged from 108,702 to 119,289 SHUs. It is interesting to note that the relative increase of capsaicinoids in the drought-stressed plants of low pungent cultivars (170% to 721%) was obviously higher than those of the medium pungent cultivars (113% to 141%). However, capsaicinoid contents of the drought-stressed plants in the high pungent cultivars were slightly decreased (3% to 8%) as compared with the other two groups. Nevertheless, the capsaicinoid yield, that was calculated from capsaicinoid amounts multiplied by dry fruit yield, was decreased under drought stress for all cultivars, except ‘Keenoo-Sakonnakorn and ‘Num Keaw Tong 80"
This study also seems to show that you will get less total capsaicin by drought stressing in most cases.
 
Reading the full report gives a slightly different story, of how cultivar played a greater role than environment. Each cultivar responded differently, from root-shoot mass ratio, cap-dicap ratio, shoot development, etc, though there were consistencies between pungency groupings.
 
There were no super-hots in the study, neither really topped much over 100k scoville. Interestingly, they mentioned Bhut jolokia, but did not include in the study. The findings that peppers with a low-medium pungency are effected the greatest by water stress is consistent with other studies. I am wondering why 1g from a single pepper was considered an accurate representation of each group, but perhaps I misread.
 
However, in our study, the significant increases in capsaicinoids were observed only for the low and medium pungent cultivars but not for the high pungent cultivars. These results might be explained by the fact that a genotype and genotype–environment interaction affected capsaicinoid content (Zewdie and Bosland, 2000), in which the genotype effect was larger than the environmental effect (Gurung et al., 2011b; Zewdie and Bosland, 2000). In addition, Gurung et al. (2012) found high stability of cultivars with high pungency, whereas the lower pungent cultivars were very sensitive to environment.
 
The last paragraph sums it up fairly well.
 
The high pungent cultivars had good water retention and showed minimum effect of drought stress on yield and capsaicinoid contents. Drought stress effects were high in the low and medium pungent cultivars. An explanation may be attributed to the different responses in capsaicinoid biosynthesis among the different cultivars, which will be studied in the future.
 
Interesting article.  ^^^
 
 
"One Million SHU ought to be enough for anyone."   :D 
Yea, I know I'm a big wimp; all the superhots I've grown will readily melt my face to goo. :mouthonfire:
 
I'm just happy if the the dang things survive the heat and bugs and storms and human foolishness.  Let them grow and be fruitful!.  ;)
 
I agree, some very interesting reading. So what I gather in a nutshell is. Growing super hots or peppers above the 100,000 SHUs in a water environment (hydroponics, aquaponics etc) will render pods with no significant loss of pungency and that growing these types of peppers in these growing conditions may actually have more benefits than detriments.
 
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