Unfortunately I lost a lot of my raspberries to root rot issues this season. We had a lot of rain and while usually my soil is fine draining, I guess it couldnt keep up this time. Has anybody ever added perlite or sand to in ground soil to improve drainage? Or does anyone have any tips on improving it?
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I had the same thing happen in my yard where i put a row in a low lying area that will likely never support raspberries. The solution for me is to make raised mounds if i want to continue.
Another solution would be root pouches.
Some varieties are less susceptible to root rot as well…but all raspberries dont like wet feet as far as i know.
A couple of thoughts
Digging down below the root zone, near your planting, to see what a normal perk test shows is a good start to diagnose your issue.
As you dig down look to see the soil profile. Every 3-4” down take a soil sample and toss it in a bucket.
If you hit a hardpan, bingo you know your issue!
Otherwise once you have a 2’ deep hole, do a perk test. If over a period of a day you see the hole is not continuing to drain down, then you might conclude that drainage is the main issue.
Mix the soil samples and fill a quart jar half full, fill the jar with water and shake to mix well. Over the next hour it will settle out in a profile showing bottom to top of soil gravel, sand, silt, a dark layer of organics. Based on the profile you can determine whether sand or organics should be incorporated into your soil. If you do not have 10%+ organics, plan on adding either compost or peat moss whichever is easiest to get in your area.
If your perk test shows good drainage over a period of several days, then changing the soil to increase its CEC, cation exchange capacity, may be your best option. If drainage is poor, check topography to see if there is a lower lying area downhill of the raspberry planting where you could terminate a drain pipe, if you were to install a perf pipe below the planting root zone. This last step is a lot of work, you may find that building up a mound is easier. Hope this helps.
Dennis
Kent, wa
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Over the years I have used sand and pumice for amending entire planting beds.
Local landscape suppliers here have sand as an ingredient of 3- or 4-way soil mixes.
Red raspberries are particularly fussy and do better in raised beds or planters.
They will need additional late spring and summer watering, but will fare better long-term in wet
autumns and winters.
Pile up what you have… that is what i do.
I have 3-4 inches of pretty good dirt (loamy clay) then red rocky sticky clay.
If I am making a bed 4 ft wide… I break up a 8 ft wide strip of (my good dirt) the very top layer that has lots of organic matter in it (grass and grass roots)… and then I rake that up to form a borderless raised bed and mulch it good.
I have never had root rot on anything, and it rains like crazy here almost every spring, and so far in August it has too. But on a simple borderless raised bed like that… the over abundance of rain will end up running off to the low areas on the side… it may pool up there, but it does not remain on your raised bed, that part drains well simply because it is higher.
I have red black and yellow raspberries in that bed in the vid, since 2020, no problems with root rot.
TNHunter
Good Luck !
I would avoid perlite, it tends to float off.
Try to build up the soil with organic matter, lots and lots of it. One of the vegetable gardens I manage used to flood every time it rained and had a lot of rot problems. Soil was garbage clay. Over the past few years I have added tons (literally) of woodchips to the aisles and sand, compost, mushroom soil, and manure to the beds.