Wanting to understand mulch


#121

Please say how you could quickly remedy excess vigor from prolonged use of mulch. Thanks. Here in fireblight country am trying to manage apples and pears for slow growth. But we also typically have brutal summer/fall droughts where mulch could be key. Trees just reached bearing age, have been deep mulched. Trying to decide if it’s time to stop mulch, just mow around trees, let sod slow the trees down.


#122

Hambone,

I’ve found once I stop mulching, the vigor calms down to normal levels pretty quickly. It doesn’t take long for the mulch to degrade here, and for the trees to suck up all the remaining nitrogen.

I add synthetic fertilizer to some of my peach trees, even though they are mulched. New peach trees and fairly old peach trees get fertilizer. New trees because I want to size them up as fast as possible to get them into production. Old trees because the vigor slows down too much and they don’t put on enough growth, even with mulch.

I don’t add any synthetic fertilizer to apple or pear trees, precisely because of the issue of fireblight. I don’t use much herbicide around pear trees also because of fireblight. I do kill weeds/grass around apple trees because they are bushier and would require a lot of push mowing under trees to keep weeds under control. I also use apogee on apple trees to slow growth.

Using fireblight resistant pear varieties, along with these other techniques has slowed fireblight to a very manageable level in my orchard so far.


#123

Thanks. When you stop mulching do you find that drought causes more of a problem?


#124

Peaches don’t need any water here, even in very dry years, as long as weeds are controlled. Established apples and pears also don’t need water during dry summers (again is weed control is maintained).

Our average monthly rainfall for the summer months is as follows:

May: 5.39"
June: 4.44"
July: 4.42"
Aug: 3.54"
Sept: 4.64"

As you can see, we get quite a bit of rain during the summer months on average. However, we also have dry summers which deviate radically from the averages. In 2012, we didn’t get but about 3/8" of any inch of rain from the beginning of May through the third week of August, at the farm. It was very hot and windy all summer, so the ground was extremely dry. Established peaches, apples and pears didn’t need water. Blackberries did.


#125

Interesting. Easy to forget how much water weeds take away from trees. Thanks


#126

But you also live where rain tends to decline when peaches start to ripen. You also have a clay soil that may usually provide roots with maximum available water most seasons anyway. There are so many factors in play.

Clearly, a thick layer of humus doesn’t quickly disappear and it will continue to release lots of N., peaking in summer when you least want it in established trees if rain allows biological processes to continue full speed ahead. Also, humus provides the most available water to trees of any medium.

My thinking is that the mulch in itself isn’t the problem, it is when it breaks down that it becomes one in some humid regions. One could scrape the surface every season or two before applying a new layer of fresh mulch. But you will likely be scraping lots of fresh root in the process, which is probably fine and may make for better quality fruit in established trees.

All that said, I mostly follow Olpea’s advice. When established trees have adequate vigor I often stop mulching and let mowed grass reach the trunks. Just as important as high brix with peaches is keeping them fairly vigorous. The worst thing that can happen is for them to runt out and stop producing adequate, moderately vigorous fresh wood. They are very prone to runting out when they suffer even fairly short periods of drought. Compromise is often necessary to get the best results overall. Growing fruit in the east requires more compromises than in the west.


#127

That’s true, at least for most years. In addition to the variances of the averages, what my monthly average rainfall doesn’t show is that from about mid July through mid August, it generally doesn’t rain much. Consequently, that’s when the peaches generally have their best flavor. It’s also the hottest during that period, so the wind and sun bake the soil during that time most years.

Here, I’ve never had a peach tree runt out, even in the bone dry summer of 2012. I’ve seen some peach trees runt out, so I know it’s possible, but I’ve not experienced it. The only time I’ve seen it was occasionally when a homeowner plants a peach tree in the backyard and leaves it unmanaged (unpruned, no weed control, soggy spot, no leaf curl sprays, etc.)

Obviously you manage the trees you install so perhaps the difference is in the soil, or the terraces. It’s my theory that the terraces promote extensive root growth because the roots are never stressed with excessive water. It can rain 4 inches in a day (which can occur here) and the roots are never submerged below the water line. If the roots do get soggy, the terraces drain quickly. Much more quickly than if the trees are planted at grade level.

I think this promotes rapid and extensive root growth, which not only increases vigor, but allows the trees to weather long periods of drought.

Too many times we focus on what is happening above ground, but as you know, what happens below ground is just as important.


#128

i only water newly planted trees when i see signs they need it. otherwise i let those roots spread looking for water. i find that it increases the overall vigor of the tree because its forced to grow a more intensive root system in search of water. might not take off as quickly as a regularly watered tree but when it does the growth is phenomenal!