The great Seattle cold-hardy avocado trial

First sprout of the season just dropped! This is a seedling of Aravaipa, and the boldest little fella out of ~80 seeds in the greenhouse this winter:

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It is funny how they have no mechanism to wait for spring to sprout. Probably since they’re adapted to warmer climates they are at an advantage if they can already be well established before summer hits.

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Last year I noticed that about half the Duke seeds didn’t sprout until well into spring, but the other half mostly sprouted in December. They all put down taproots in December, though. The ones that waited grew just as vigorously during the growing season, but there is definitely variation among the seedlings on whether to wait until spring.

The greenhouse does get pretty warm on sunny days, too, so it’s possible they would be waiting if they weren’t getting those 65-75° days a couple times a week. The coldest it’s been in there this winter (other than a brief period when I tried out turning off the heater) is mid-40s, and some nights it’s been upper 40s or even low 50s:

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I’ve never tasted a Fuerte before, so I ordered a box of them, which came today:

I’ll grow out the seeds even though I don’t expect them to fare very well, since I like to include as many varieties as possible in the trial. Greg Alder has a nice write-up on this variety’s somewhat apocryphal origin story:

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Looks like the terminal bud on #138 got a little burnt by the low of 24.9°F on Sunday night, but otherwise it looks remarkably good despite the buds somewhat waking up already:

This was the Sunday-night freeze, hopefully the last mid -20s of the winter, but that’s perhaps to optimistic:

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These are really tasty! We’ve eaten three that ripened so far, here’s one of them:

They have a really nice nutty taste and smooth, creamy consistency. Up there with a good Hass, even. They are also very easy to peel and slice for sandwiches.

I would be surprised if these future seedlings are hardy, but I’m hoping I’ll be surprised.

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You have inspired me my friend.

I let my baby ancistrus plecos clean the pits in a fish tank. Left them till they cracked.

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The seeds of Fuerte seem eager to germinate! These are after 3 days and 1 day (the one that has opened widely was removed from the fruit 24 hours ago):


The cultivar was named for its vigor according to that Greg Alder piece, and it seems to have equally vigorous seedlings.

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My favorite avocado growing up. I remember getting bags of 10 for $1 at the stands around Escondido and Ramona.

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@swincher, how long do they take to sprout typically after cracking? I have never done an avocado before.

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There is huge variation between seeds, even under similar conditions, but temperature and light both influence them.

I’ve had some fall-sown seeds not pop until March (4-5 months later), even on heating pads under grow lights. Other times I’ve seen seeds already fully germinated in the fruit. And everything in between.

I’d say the median germination period for seeds in the greenhouse in winter, but on heating pads under lights, is a little under one month. Indoors, they usually germinate faster because the overnight lows are warmer, so maybe 2-3 weeks. But there are almost always a few that sprout way before the rest, and a few stragglers that wait a few months.

It sometimes helps to remove the seed coat, which can hold them closed longer (until it starts to decompose), or to cut the top off the seed, if the dividing line isn’t totally straight (this is less often a problem with the more round seeds like Hass, and more often a problem with pointy seeds like Aravaipa and Duke). If the line separating the two halves zigzags near the pointy end, the seeds often get stuck closed. But cutting the top can introduce mold, so should be done sparingly.

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Thanks for the info. Both of mine sat in the aquarium for about 10 days. They both cracked like the San Andreas fault the same day, that’s when I pulled them out. The baby ancistrus plecos (by the hundreds) loved sucking the outer pit. It was like the sanded it for me. They definitely ate away several layers of seed shell.

Patience mode time now. They are ontop of a 120 gallon tank so the temp is about 80.

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In your photo, it looks like the seed coat is still intact for both of the seeds, at least on the top side, but if they were already cracking open on the bottom side, then I would just wait rather than pulling them up to peel them off. Usually the taproot emerges first, and the top shoot waits another few weeks to a month after that.

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Thank you for the input Winn, I appreciate your experience.

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There is a huge difference between this year and last year in terms of avocado flowering. Duke, which was by far the first to flower out of the trees that flowered last year, is barely budding out now:

Last year, it started like a month earlier and looked like this by around this time in February:

Duke still seems to be furthest along, though, at least out of the trees that flowered last year. Joey is at about the same stage, but looks like only vegetative buds, same as last year:

Aravaipa is nearly at that stage as well, though it had only one small flower cluster last year and once again looks like mostly vegetative buds:

Linh (on the same multi-graft tree) is still basically entirely dormant:

The furthest along of anything in the greenhouse is the unknown variety “Rincon Valley” collected by @jsteph00921 from a tree growing in a public parking lot in that valley:

That is grafted on a potted Zutano seedling, and surely isn’t big enough to fruit, but I’ll let it flower so I can collect pollen anyhow:

One other interesting thing from the project, this Duke seedling has recently aborted a bunch of otherwise healthy looking leaves that were the most tender leaves when it experienced freezing temperatures more than a month ago:

The part of the stem that was tender during that freeze also turned a pink/purple color that the older and younger stems don’t have as much of:

I’ve never seen any avocados that seemed inclined toward being deciduous, but this is the closest I’ve seen yet.

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Winn:
What type of predator control is black card in pic #2?
Chris

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They were green lacewing eggs, which I got to combat aphids. Any cards that the slugs didn’t find (and scour clean) hatched into larvae that were promptly eaten by spiders. I later released ladybugs in the greenhouse, and they cleaned up the aphids, but were also mostly eaten by spiders.

No aphids this winter, though! One of the trees has a bad case of soft scale that I’ve had to attack with cotton rags and soap, I wish I knew of a good predator to release that would eat scale! I’ve seen a few slugs going after it, but never any other predators.

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Yeah, I tried green lacewing eggs in ghouse for scale but ants devoured them all. They must be a prime item on the menu!
https://growingfruit.org/t/green-lacewing-trial-for-ghouse-not-so-good/
There’s also this predator for scale- but too expensive: Red Scale Parasite (Aphytis melinus)

@Bradybb 's suggestion to use diatomaceous earth to control ants really worked. After a DE dusting, I’m ready to try green lacewings again.

Several ladybug releases throughout the spring/summer/fall have worked for me to keep down the ghouse aphid population …but I only found one lone ladybug yesterday on citrus after the release of hundreds (thousands?) throughout the year!

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I’m lucky I’ve never seen ants in the greenhouse, they will definitely defend their farm animals (aphids, etc.) from any and all predators. I’m guessing the healthy population of spiders helps on that front, or maybe I’ve just been lucky so far and ants will be my next greenhouse battle!

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Nearly two weeks later and still very little progress on the avocados. Here’s Duke now (different bud than the quoted post, but Duke’s buds are all around this stage now):

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