gary:

I know this isn't your question, but if you'd rather have apples every year thin heavily and early next year. It's pretty obvious you didn't thin enough last year....or maybe you like a year off.

With very little fruit set the year before because of the weather I did get a bit greedy. Your comment is well taken and no, I don't like a year off especially with the weather cooperating this year. You never know what the weather will be like next year.

My Macoun apple did this last year. Because I didn't thin the year before. Being a newbie to apples I just loved the huge amounts my Macoun gave me so let it slip, reading later that Macoun are prone to do this. So if I thin them this year will it kick back in or does a tree just go into biennial bearing?

John:

Heavy and early thinning will solve the biennial issue. Or at least it always has for me. I've seldom had an apple or anything else take a year off. My Bosc did one year. I got greedy too after waiting 7-8 yrs for it to bloom the first time. I've still only gotten that one good crop. Froze out the last two years.

Some apples are stubbornly biennial. For example the classic reference Apples of New York mentions "biennial" on about 100 of the apples it lists. On some apples you can get them annual with significant thinning but not on all. Most modern apple varieties are not prone to biennial bearing as it has a big negative economic impact for the grower. I grow lots of old varieties and have many biennial bearers.

Scott

Scott:

That may be true but I once grew about 50 heirlooms. None that I remember were biennial. Now it could be that our higher light level and long growing season pays a part. But I'd suspect it's also related to amount and earliness of thinning. If one thins after June drop there may not be much effect on return bloom.

Even with modern varieties commercial growers are very concerned about this issue. They want to knock the excess blossoms out before they're even pollinated with growth regulators. In fact all they want pollinated is the king blossom, the center one that blooms first. Then they want to cut off pollination so that the others aren't even pollinated.

After the Michigan apple crop froze out a couple years ago extension agents spent all year talking about the need for aggressive thinning the next spring. Thin early and hard or you'll pay the price down the line.

This post was edited by fruitnut on Mon, Apr 21, 14 at 19:05

Fruitnut, You say to thin heavy and early, When would you say is a good time to do this? I'm in zone 6 PA.

I start as soon as the fruit is big enough to do the job, about 1/4 to 1/2 inch. Aiming to leave 2-3 times final crop load. For my trees that's about one apple per cluster on first thinning. Final thinning leaves about one apple per 3 clusters. With the good return bloom I get this is plenty of fruit for me. Others might need more. And in a humid climate you probably need to prune more open than me meaning less fruiting spurs.

I'm finished when apples are 3/4 to one inch. But dang frost I can hardly remember thinning. Seems ages ago.

Fruitnut, I'm impressed you got no biennial bearing on those heirlooms. I am in the opposite situation with many of mine, they are in a less than optimal area for sun and I need to do late thinning since the Surround is not perfect on curculio and backup apples are helpful. I usually thin to two per cluster until the curculio season is over.

Scott

I have observed a correlation between biennial bearing and sunlight exposure and I believe the further south you live the less a problem it is. Commercial growers here struggle with it on certain varieties and Fuji is known for this tendency no matter what you do here.

On my own property I have 3 Goldrushes that were treated the same last year (thinned very early but maybe should have done more) - the one with the most light exposure has good flower set, the one a bit more shaded is splotchy and the one in the most shade hasn't a single flower.

As a general rule, earlier varieties are less prone to this problem and Macoun is not terribly biennial here. I manage trees that are never thinned that bear 2 out of 3 years- at other sites unthinned trees are reliably biennial. At one of these biennial sites for Macouns I also don't thin the Macintosh, Yellow Transparent, Fallawater and Wealty, but they bare most every year anyway.

Trees are assumed to determine early (within 3 weeks of petal fall) whether to set fruit the following year, but I remember a lecture a commercial grower gave where he had seemingly irrefutable evidence that events in late summer can also be crucial. I wish I had written down what he said and if anyone knows anything about this please post. Obviously they do have to begin the formation of next year flowers early.

If a tree bore no fruit the previous year and is loaded with flowers the following I will strip off the flowers from every other spur as early as they start to open- then thin fruit later. Once a tree falls into biennial bearing it can be a struggle to straighten it out.

I agree with Scott that many heirloom varieties simply can't be made annual producers- at least on certain rootstocks at some sites. I have a very healthy Ashmead's Kernel on M7 whose flowers were frozen off in the spring of 2012 and yet had only 3 apples the following year when every other variety was loaded. This year it has flowers again. I'm still hoping there is some trick beyond stripping off every flower from some of the branches to make this variety more reliable.

Dam, I need to go spray oil- this forum is much too addicting.

The thing I do that's probably most responsible for annual bearing is not leaving too much fruit on the trees. I probably have 50-60% of a commercial crop. But that assures bloom every year and more importantly to me, it assures high quality fruit.

If degree of shading affects return bloom that would tell me the shaded trees were carrying too much fruit for the conditions.

I recall tasting 'Early McIntosh' at an orchard I worked at years ago. It was so good I asked the owner why he did not grow more. His response was for me to come back next year and I would know why.

I did work for him next year. The same trees had just a few
apples on them Terribly biennial. Some old heirloom varieties are prone to this no matter what you do. One of the reasons why some varieties from the 19th century are
no longer economically viable to commercially grow.

I too am worried about my apples this year. Last year was
a bumper crop after having no apples in 2012 due to spring
frosts. I hand thinned heavily last June and got most of the trees done ok.

I missed one tree due to lack of time. Some unknown golden variety that ripens in late Sept. The apples never sized up nor colored well as too overloaded. I fear it may
bear little this year but I will know soon. I knew better
but time is sometimes my enemy in spring.

Just have 2 of the same trees... have them alternate bearing. One heavy one year, the other the next... Problem solved! :)

Honeycrisp is biennial, or so i've read...

Hi total newbie here and not trying to hijack this post honest but about this biennial thing.

By newbie I mean I was out looking for vines and the lady said we have this Granny Smith Apple Tree on sale. I said can I grow that?! 20 bucks later I was sold.

I got it in the fall and she told me to plant and prune. I watched a video on YouTube and went outside. I have an "open" center as well it came that way so I cut all the other branches off except those two.

NO clue how old it is but I do have a ton of leaves coming in. Of which I must say totally excited me. I read about the 5-7 years prior to fruit but if you have no clue how old it is well...no clue.

Did I do the correct pruning to have annual apples? Do I need to cut all the leaves coming in???

Apples will bear sooner with as little pruning as possible. Instead train the tree to the shape you want. Tie the branches where possible so that they are about 45 degrees or slightly less above horizontal. Don't allow any branch to become bigger than 1/3 the diameter of the trunk. If it gets bigger than that stub it back to a couple buds so as to form a new smaller branch in it's place.

By all means don't cut off the new leaves now.

I did go out and buy a Macoun just for that reason. So if one is talking the year of I'll have the other one. My Gravenstein seem to do that also. I have two of them so I'm gonna see about doing that.

Fruitnut, I wonder if the commercial growers thinned to your level whether they could defeat their problems with Fuji and other inconsistent varieties. I'm sure there is sometimes more at play than fruit load or I would have had Ashmead Kernel apples last year. The tree is on my most sunny location. Have had similar problems with other varieties at other sites, including Fortune when young.

I think proper crop load would solve most alternate bearing issues but certainly not all. My last Fuji planting bore fruit yr two and every year after. And it was a lot of thinning. Guess that is the downside of my method. There is a tremendous amount of thinning each yr.

You and I both know it's much easier to under thin than over thin. I think that and being a little greedy gets many folks. Shoot I like to see a tree loaded down with fruit also. Makes me feel like I really did something great.

Thing I see, from a howeowner growing fruit perspective, is that if you over thin...you might not end up with anything due to squirrels/bird damage....so if you leave an extra amt of fruit, you can factor in those losses and still end up with something. Squirrels take a huge toll on apple trees around my yard...even after trapping many of them.

FN what I'm actually suggesting is that if one could determine the actual potential consistent crop load for the various commercial cultivars then commercial growers could regulate their harvests to what the trees could efficiently produce annually. Obviously this is there aim already. This would inevitably be a ballpark figure as weather conditions affect a trees ability to store energy.

In Texas you have (depending on time of first and last hard frost, year to year) a much longer growing season than those in the NE . I think this might give the trees a considerable edge as far as storing energy for its needs and ultimately to get consistent cropping.

However, your higher temps and lower humidity levels are much more prone to being beyond an apples trees ability to function efficiently. The stomata must be closed for a good percentage of the hours in normal summer days there. Under plastic, this probably isn't the case, though, because of the high humidity there.

Anyhow, I'm pretty sure there is a complicated choreography of factors involved in reliable bearing.