Jujube fruit set if you don't have hot dry summers


#282

makes me think that too much water(on top of high humidity)--- just as it is with extremely low water, results in poor flower set/fruit drop.

a good drying-out-in-between-waterings seems to be the key, to simulate arid conditions.


#283

When do you girdle, late winter when still dormant or right before flowering or after flowering?


#284

These are in the field and don't get supplemental water. The only water they get is what nature provides.

However, you make a good point regarding water/dry-out. That is exactly how I water my trees in the Rootbuilder 2 air-pruning containers. I immerse the entire container in a tub of rain water and allow it to fully saturate. I don't water again until the container is light. With these air-pruning containers, I find it very hard to water on a schedule. They are so well drained that depending on humidity, wind, the stage of growth and other factors I find top watering difficult. When a tree is first transplanted to a larger container, it is easy to top water and saturate them. However, as roots are pruned and more and more upstream branching occurs, the roots fill much of the air space in the mix. Water infiltration becomes much more difficult over time. You have to add water, let it absorb, add more, and continue to repeat the process. With over 100 containerized trees this is too time consuming. I have found that watering trees based on the relative weight of the container and doing a full saturation by dunking them works the best for me. It also makes efficient use of rainwater that I collect since my city water is not ideal.

This is exactly the process you describe to simulate arid conditions.


#285

Jack,

Next year try to graft a wild jujube scion to one of your jujube tree for an experiment. The two Honey Jar Jujube trees that I grafted the wild jujube scions onto are so loaded with baby fruits and the rest of the other variety of jujube trees are also set a little better than last 4 years. This is the only thing different that I could pin point to a better fruits set beside the dry and hot weather.

Tony


#286

Now that is an interesting idea. I'm a bit afraid of native jujube root suckering in my application, but if I grafted a scion to tigertooth roots, that would not be a problem. I presume you are talking about top working an individual branch, correct?


#287

my theory is that their wandering roots run deep and wide when planted in the field, which equates to full hydration in areas with much higher rainfall than deserts, i.e. surface soil dries up so much faster, which may falsely indicate drying out, when in fact the deeper roots and surrounding soil are still soaking wet.
in potted conditions, we could literally wait until the pot gets really light, or at the early stage when the leaves start getting droopy--before watering again.
jujus actually use their fruits as water reservoirs. Fruits get wrinkly and prune-like in hot and dry conditions, before the leaves start getting droopy. From a survival standpoint, we could conclude they have a 'biological need' for their fruits in dry conditions, and when there's a need, there must be a physiologic incentive to produce them, as well as a need to hold on to them--preventing fruit drop.
fruits will shrivel and drop off in times of severe drought, but this is only when the plant does not get watered soon enough. Thankfully we seem to be able to water them just in time before fruits drop in en masse. And by doing so, the trees seem to respond by holding on to the fruits more 'dearly' :grin:
we had 115F weather yesterday, and the first pic shows a couple of black sea juju fruits wrinkled as if beyond resuscitation.


the next picture shows the same fruits the day after(today), status post irrigation. The top juju even produced the typical 'anthocyanin blush' sunscreen, practically overnight.

and the same fruits were quite capable of doing it over and over, as long as the trees are watered soon enough. Here are two successive pics on days we were late(again) in watering them, more than two weeks ago


#288

perhaps Chien has a different take on this, but as i see it, girdling before flowering is best-- especially just before the stems leaf out. This way all the food energy produced by the leaves will be 'stuck' above the girdle as early as possible, effectively maxing out the surplus and encourage fruit production


#289

That is what I was thinking. I have two problems, flowers not pollinating and those that do drop. Girdling will probably help with fruit drop not sure about pollination, which is my main problem.


#290

you may already have enough varieties for pollen.
li is self-pollinating, and is supposedly a night bloomer. It is one juju which personally and consistently witnessed to be self-pollinating, having watched a lone li in a university campus for almost a decade now, and very productive all these years. Shanxi and hj are also reportedly night-bloomers, so li should be a good donor.

sugarcane is supposedly day-blooming, but should get enough pollen from the other three since pollen release and receptivity of day and night bloomers may coincide, even if briefly.


#291

It isn't necessarily a good thing to do this though. In comparing the fruit that Roger Meyers grew (and shipped to me) vs the fruit I grew, the brix was in the same ballpark, but mine had a much crisper texture. Now, it is possible that the shipping is what caused it, but it could also be the dry conditions in which it was grown. Maybe when I am growing enough excess fruit to experiment with, I'll leave some in a box for a week and see how it impacts initially crisp fruit.

But, it seems to me that the water content could be a big factor in how crisp the fruit is. One question is if only the final water conditions impact the texture, or does the fruit going through a shrivel/re-hydrate cycle have a lasting impact.


#292

as you mentioned, one could expect that, since shipping from coast to coast will surely dehydrate, and since the shipment is from a dry region. Additionally, the fruits you received from Ms Meyer may have been harvested in the creamy stage, which will ripen by tanning up, but isn't exactly optimal.
the farmworkers don't really bother much about fruits ripening further on the trees, and just harvest them in one lumpsum, and at a slightly immature stage, since fruits last much longer that way.

from my experience, the shrivel-rehydrate cycle does not impact the fruits, only the final hydration condition.
i actually think the other way-- that the 'refreshing factor' and flavor are intensified with repetitive water-/heat-/ solar radation- stress(just as brought up at least a couple of times in the other threads).
antioxidant production is stimulated by stress-- apples and peaches(and many other fruits) are better tasting and have more intense colors when grown under the heat and hostile radiation of full sun compared to those fruits borne under shade. I see the same trend with jujus. *Some farms even line the ground with mirrors to tan and warm the fruits under the canopy shade.


#293

Honey Jar are looking real good this year. It has fruit on each leaf. I hope this will be a new normal for me. Btw, the 5 yrs old Lang with lot of grafted varieties also set better than before.

Tony


#294

Tony, I have worse fruit set this year than last year, probably due to lots of rain during bloom this year and drought last year. I have one small Honey Jar graft that set like yours earlier this year but it dropped all at about where yours are now. My other varieties set sporadically with a light crop. My Honey Jar looked much better than the others as far initial set but in the end let my down. Hope yours does better.

I do think if I can get more size on the graft it will be one of my more productive ones.


#295

Mark,

I am trying to figure out what were the reasons for better fruits set this year. We got hot temp in the 90s for at least 3 weeks now. Lots of pollinators out right now buzzing. Grafted wild Jujube branch for cross pollination. Jujube trees are getting bigger.

Tony


#296

looking good!


#297

Check out this massive jujube farm in CA.

Tony


#298

definitely a major source of li jujubes being sold in many stores here.


#299

Thanks for posting that. I went to their site and they have two jujube crops- one from mid-July to mid-August and another in Oct/Nov. I've emailed them to see if they'll ship me a box. I doubt I'll have enough on my trees this year to make my wife happy (or next year probably) and I definitely won't have them in July.


#300

My Li set fruits like crazy this year. I wish I can pin point the reason but I am very happy with the outcome.

Tony


#301

Those looked fantastic, Tony.

All my 3 newly planted jujubes are flowering. Realistically, how many years before I could expect the fruit to stay on to maturity, please?