Growing Organic Berry Plants:
Managing Annual Fertility
for Your Berry Plants

Caring for your berry plants

Here is a list of seasonal duties that we perform (well, we try to perform them, but sometimes weather and life get the better of our intentions) on our farm, ensuring healthy and productive plants.

Feeding the Blueberry and Raspberry Plant:

Too little or too much fertilizer can be bad for any fruit producing plant, as it can result in nutrient imbalances and toxicity.  Many of you who order and correspond with me have asked me what we do here at our farm, so I am going to put it here for all to see.  We've spent a while playing around with different formulations and timing of applications, and feel we have a pretty good system. So, here is our fertility schedule for our blueberry plants (click HERE to jump down to the care for raspberry plants).

Growing Blueberries Organically:
Annual Fertilization Schedule

Early to mid-spring, usually when the daffodils are in full bloom, we top-dress our blueberries with 1/4 to 1/2 pound Re-Vita Pro fertilizer (5-4-3), depending upon the size and age of the plant (more for older plants).
(any balanced, organic fertilizer will do, and if you use alfalfa meal/pellets, just double the amounts listed for the Re-Vita.  Fox Farm sells an organic, acid-loving plant fertilizer that is great for blueberries)

After blossoms have fallen, we begin the liquid feeding of our plants.  This is given to them every two weeks through August.  It is delivered though drip or hose line, and is applied to the root zone (during fruiting) and foliage (from bloom to green berry, then post-harvest).

Liquid Fertilizer Recipe

For 1 gallon of mixture, add these amounts to 1 gallon of water:
Neptune's Harvest Fish Fertilizer (2-4-1).......2 Tbsp.
Maxicrop or other kelp (liquid)..................½ Tbsp.
blackstrap molasses.................................½Tbsp.

Each plant can receive enough to get good saturation, but don't overwater.  We usually irrigate the day before applying the liquid fertilizer mix, or apply after a rain shower if it fits the schedule.  Usually on mature plants they get a 5 gallon dose, younger plants less.  If you planted a blueberry from us last year, it could get 1-2 gallons of this mix, depending upon its size (lowbush less,  highbush more).

If you would like to give the plants a foliar feeding of this as well, go ahead and just spray them to dripping with the above solution.  However, I would advise using the liquid mix only on the root zone of  mature plants with fruits that are ripening (so the berries are not "fishy" tasting).  After harvest is done, you can begin foliar treatments.  I have found increased production and vigor in our  plants the following year when treated with this mix up to the end of August.
In areas of the country with alkaline soils and water, I strongly recommend using the soil-less mix method for planting and growing blueberries.
Top dressing the planting area each year with a shovel or two of sphagnum peat moss will help maintain acidity.

The last aspect of a good fertility schedule is mulching, which eventually breaks down to provide nutrients to the plants not found in the purchased fertilizers (in fact, one of the facets of using the fish fertilizer is to add nitrogen to the mulch so microbes can break it down more effectively and release those nutrients for your plants use).  Whenever we can, we use shredded oak or maple leaves, and pine needles (these are just the best, so those of you in the south take advantage of the baled pine needles often sold at local nurseries or garden centers).  Shredded pine bark will last two to three seasons, but should be dressed if you start to see bare patches in its cover (excellent places for weeds to get in, and they will grow like crazy if they get started).  Mulches should be at least 3 inches thick for blueberry plants, and coarse so that water percolates through the mulch easily (that is why the oak leaves need to be shredded or chopped, otherwise they deflect water from the growing area).

That is it, rather simple, yet the old saw "A stitch in time saves nine" is true as ever.  Proper care and feeding results in the best production and health for your plants.

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Pruning Your Blueberry Plants

I am only going to give some basic precepts here, as there are many fine books and references (which I have always used and found to be effective) available.
First, every spring, look at the bush and prune away any dead or broken branches or stems. 

Second, you want to remove any twiggy, horizontal  growth near the base of the plant.  These stems will never result in anything, and they just sap energy away from the plant, reducing productivity.

Last, you want to keep the bush open, so sunlight can penetrate all the way through the bush.  This generally means getting rid of excessively twiggy branches and stems, which usually only produce smaller berries anyway.  This may decrease your yield slightly, but will increase the size and quality of your berries, as well as encourage new growth from the crown.

For the plants you purchase from us, you should only have to do the first two steps during the three years after purchase.  The following years may see the need for the third step, as well as regenerative pruning.

For regenerative pruning I will refer you to Barbara Bowling's book
 The Berry Growers Companion, which is a great reference for care and management of many berry species.  This is a great all around book for the backyard grower.

For those of you desiring a more in depth book specifically about highbush blueberries, Dr. Robert E Gough's book
The Highbush Blueberry and Its Management is excellent.  Dr. Gough is renowned for his studies and illumination in the care of highbush blueberries.  The book, however, is very much written for larger scale, commercial production (non-organic), but is still filled with information useful to the small or backyard grower that desires more technical insight.

 

Growing Raspberries Organically:
Raspberry Care Schedule

Generally, blackberries and raspberries require less attention to fertility than other crops, but a good schedule does increase their productivity.

In late April, usually when the redbud and serviceberry are in bloom, we top-dress our raspberries at 1/4  pound Re-Vita Pro fertilizer (5-4-3) per foot row, or a half-pound per 3' diameter mound.  
The next round of fertilizer will occur right at blossom time, at half the rate listed above.  You can also start the liquid feeding schedule we use on the blueberries once the canes are up and growing (for fall bearing raspberries) or have sprouted and begun flowering (for summer raspberries and blackberries).  Suspend any foliar  liquid feeding about 2 weeks before the  berries are beginning to ripen.  I've found increased vigor and yield, better pest and disease resistance, and less winter-cane kill in our brambles when they receive the liquid fertilizer treatment up to when the daytime temps are consistently less than 60 degrees (usually mid-October here in Brown Co., IN).

A lot of places and books warn against mulching raspberries, but I have had good luck with it.  The key, I think, has to do with the type of mulch.  Use a coarse mulch, like pine nuggets or straw, that dries out readily and doesn't mat.  Things to avoid using are grass clippings, un-shredded leaves, hay (filled with weed seeds...believe me!), hardwood bark mulch, and wood chips.  Grass is the worst enemy in a patch of raspberries, so make sure you don't let any get started.  Wheat straw will have wheat coming up in your patch, but just cut it out at the base and that will do it in (wheat is not perennial).  If you can find rye straw, it's great, and usually seedless.  We usually mulch our patches every other year, after we see emergence and thin the canes.  Fertilize with the granular material right before mulching, if you can.  Remember that late is better than never, and if you don't get around to mulching and fertilizing them until May (late), they will totally appreciate the attention.

Heavy Soils and Brambles

We have very heavy soil here in County Brown, IN, and while that's a good thing during droughts, it can be a killer in extremely wet weather.  Through trial and error (and error and error..), we've found a way to strike a balance between weather and soil conditions so that our brambles can be very successful.

Ridge and Mound Planting
The most susceptible brambles to seasonally wet soils are the red raspberries, especially the summer red raspberries.  Yet, we get very reliable crops every year, as we plant in ridges (or mounds, if you have just a few plants here and there).  In a row 18" to 24" wide, we have a gradual rise to the middle of the row, so that the above "grade" height of the ridge is 6-8".  That little bit of increase above grade seems to do wonders for our production, with ridged plantings giving nearly twice the amount of berries in wet years as non-ridged plantings. For mounds 3' across, the same applies:  a gentle rise to 6-8" above grade.
 Of course, in dry weather, you'll want to have an irrigation line down, but that is something you should be prepared to provide anyway (we usually soak the row with 2 gallons per foot row, applied at half-gallon per hour through drip lines during hot, dry weather, twice per week).

Blackberries, black and purple raspberries, and the Anne Golden fall raspberry, do not seem to benefit nearly as much as the red raspberries do from this technique.  The Lauren red raspberry really appreciates the ridge method, and seems to require it for best production.

Pruning your brambles

Fall Red Raspberries (primocane producing)
and Summer red raspberries (floricane producing)

Fall red raspberries are primocane fruiting brambles, which means they produce a high quality berry on the current, new growth arising from the soil each spring.  Do not prune these primocanes, but let them grow as big as they want.  Trellis, stake, or tie up any canes that get taller than 4 feet, as they are likely to fall over when loaded with fruit.
The cane maintenance of this type is very straight forward:  at the end of the season, when frost has come and the canes have dropped their leaves, cut all canes to the ground.  This will ensure a very long lived stand, as well as the highest quality and yield of fruit possible.

Summer red raspberry pruning coming soon.

 

Black and Purple Raspberries and Hardy Blackberries (floricane producing brambles)
 These varieties have a different growth habit than the red raspberries. They arise from a crown, with 5-10 canes arising on a mature plant. Fruiting occurs on the laterals that develop on these canes. Pruning the plants 3 times during the year will help to make a sturdy and self-supporting plant, without the need for a trellis.

In Mid to Late Winter (Feb-March) Prune the dormant laterals of the floricanes, which will help with larger fruit, more air circulation, and a lower incidence of rot in the upcoming season. Prune the laterals of black raspberries to 7-9 buds, the purple raspberries 8-12, and erect blackberries 18"-24".

Early Summer Tipping (Late May-June) Tipping is when you are removing 2 to 3 inches of the tips from the growing primocanes. This is done to help stimulate lateral growth and branching on the primocane (for flowering and fruiting next year), and needs to be done early so that the plant has enough time to grow strong laterals. Tip black raspberry and purple raspberry primocanes when they are about 3-4’ feet high, and erect blackberry primocanes at 5-6’ high (in extremely windy areas, or where one has experienced blow-over of blackberry canes,
try tipping the canes at 3-4’).

All the canes on a plant don’t grow at the same rate, so you will have to check on slower growing canes. This is also the time to select the strongest primocanes for next year’s season. It is good practice to pick the strongest 5-8 canes on a mature plant, and remove the rest. Further spacing between plants will allow you more canes per plant. Plants grown in their own 2’x3’ bed could have up to 10 canes, as long as they had ample air flow around the bed. You can also try trimming some at lower or taller heights, and observe the results. They may be better for your needs.

Late Summer Culling (July-Fall) After the floricane is done fruiting, it will begin to die back. At this time, you want to use really sharp loppers or pruners and remove the floricane all the way down to ground level. Don’t prune into the crown, so if it is tight, it is better to leave a stub than risk damaging the crown. After removing the cane, burn or dispose of it away from your growing area. This will ensure longevity in your bramble stand, and generally increase the vigor of the stand so that it can endure for over 20 years, and maybe longer.

 

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Hopefully will be adding pictures here as time allows.