How large should containers for blueberries and raspberries be? What kind works or doesn't work? What do I do with the plants and pots in the winter? Does the bottom need to have gravel and/or broken clay pots for drainage? Do the containers need to have hole(s) in the bottom for drainage?
Blueberries (dwarf variety) can be grown in 5-gal containers. There is a question on whether raspberries can be grown in containers due to their spreading root system. I do wish someone would experiment with them just to see what happens! I have an extra plant and I just may try that one myself.
GrayThumb, I am not experienced in growing blueberries in pots but I am planning on ordering several to try this season. The nice thing about growing potted blueberries in the ability to easily adjust pH as required to the acetic side. I have been reading a number of taplas' postings on containers and had originally thought the same thing as you about adding rocks to the bottom of the container for drainage and have since changed my mind. Hole(s) in the bottom of the container are a must according to tapla and a wicking system is probably equally as important. I have some sheets of wicking material which I purchased several years ago and will use a strip of this material coming out of the bottom hole to remove the PW (perched water). It is recommended that you plant several varieties of blueberries as well. I am going with Frank's recommendation and using dwarf plants for these containers, however my containers a several times larger than 5-gallons, but they can easily be moved about with a dolly to protective shade in the heat of the summer to protection from the severe cold here in the winter. I have a deck on the north side of the house which will work fine for the shade needed in the hottest part of the summer, and a large shed for them in the winter or possibly my 8' x 12' hoop house. There are blueberry varieties which can with stand winter temperatures in my zone (3-4), however I think it is best to give them some protection at least during the first couple of winters. I am anxious to see what type of feedback you get here GT.
You do need to offer some protection for potted blueberries in the winter. Even putting them in a cold garage will help. My blueberries are all inground and go thru the winter very well. I do mulch though. I have the high bush varieties and some are at least 30 years old. Mine only fruit every other year though there is some fruit in between just not enough to pick so I let the bird get them. I fertilize with compost basically.
I grow dwarf blueberries in pots. In the fall I sink them down into the edge of my mulch pile so the top of the pots are even with the mulch, then put some more mulch about 2 inches deep into the pot around the base of the plants. I've only lost one in the past few years, and I believe it was because we had a huge ice storm. My biggest problem is keeping the birds and squirrels out as they get ripe.
Get a cat! I really don't like cats but one day this baby kitten just showed up on my back deck and moved in like she owned the place. The starlings which use to invade my corn patch soon found out that was here jungle and the mouse problem simply evaporated. PK spends the day in the garden with me rolling around in the dirt and occasionally flipping a mouse at me to let me know she is earning her keep.
The pots are 3 gallon size, maybe 18 inches deep, the bushes are dwarf, so they get about 2 feet tall. I'm not sure of the variety anymore, sorry. I do know I bought them from a vendor listed on DG with a high rating.
A farmer friend of mine told me to use pine needles as compost and as mulch for blueberries. Haven't tried it yet cuz I just gave away all my potted blueberries in anticipation of our upcoming move but I will once we do get moved. Good luck!
I went to a seminar at the NW Flower & Garden Show this spring specifically about growing raspeberries in containers. The speaker was Theresa Knudson of Raintree Nursery. Here are the steps she said to take.
To grow raspberries successfully in a container:
1. Select an everbearing (or primocane) variety that produces fruit in the first year of growth. ‘Autumn Britten’ (sold at www.raintreenursery.com) is a good choice for most of the US. Plant the bush in early spring.
2. Plant in potting soil and add lots of organic matter. Make sure to spread the roots and direct them towards the bottom corners of a 10-20 gallon container (a half whiskey barrel works well and is 20 gallons). Make sure the container has a drainage hole.
3. Place in a sunny location.
4. Water adequately (when the upper two inches of the soil dry out when you place your finger in the soil).
5. Fertilizer regularly with 20-20-20 fertilizer or organic fertilizer, following label directions.
6. After harvest in late November or early December, cut the canes (branches) off a few inches above the soil level. New branches and fruit will grow the following year. She didn't say what to do about protecting the containers over winter. In zone 6a, it may not get cold enough to need to bury the pots.
I am growing a blueberry for the first time this year, and the nursery owner told me to plant into a mix of peat moss and bark mulch-50/50. I couldn't help but add about 1 shovel of soil for each 4 scoops of moss and bark, it seemed like a good idea. Anyway, I have lots of new growth. I'm using 25 gallon black plastic nursery tree planters. I layered about 1 inch of straw on the top. I'm hoping to use pure worm casting as fertilizer in the spring.
I tried blueberries in HEB's one year and failed. I think they got too wet and they like quick-draining soil.
This year I ordered a Top Hat dwarf blueberry. It's in a 6-in clay pot right now and growing like a weed. It's been so hot I've had to water it every day but I must be doing something right.
I have a question about chill hours. I live in apartment so I can't just put the blueberry pot in the ground over the winter. I'd bring it in like I do with my citrus but I thought blueberries needed chill hours to bear fruit. Could I leave it out in the early fall? Or should I just wrap it well and insulate it? I have a closet off my balcony where it would be out of the weather. (I just need to remember to water it now and then.)
I have 2 new blueberry plants. One is a Lemonade Blueberry and has lots of berry buds. I want to plant it in a large pot, but it looks like I need to buy peat moss and I have never looked for pine mulch, but will need to I guess. I have acidic fertilizer for the gardenia - should I use this too? I was just going to use the fertilizer with potting soil and my homegrown compost.
Thank you for the informative website. I planted one (Sunshine Blue) of the two from it's 6in pot to a 15 gallon pot using peat moss, some homemade compost and good potting soil. The second one, the Lemonade Blueberry has some spots on the stem and leaves, that may be something bad, so plan to take it back to the nursery for an exchange. When it comes home, its matching 15 gal pot, 1/2 full now, will be waiting. I plan to put them on the edge of the patio where there is shade in the late afternoon. It gets VERY hot here in summer and from what I read, some shade may be called for. But, since they are in pots (albeit heavy) I can move them in or out of shade as needed. I can water with vinegar added which I read here or another spot.
My update on blueberries and raspberries in containers: I ordered and planted 6 raspberry plants (everbearing yellow) which I am raising as annuals (fall bearing only). Five I planted in the ground and one in a container (2x2x2). The one in the container is taller than the ground ones, but all have flourished well. As for blueberries I ordered 6 plants (dwarf) 2 each of 3 varieties and are potted in various sized containers. All are flourishing well so far though I do think I'm going to replant them in the ground next spring. Espoma puts out plant food, etc for all kinds of plants, both organic and non organic. They also put out a soil acidifier which I am using on my blueberries. I do want to buy some more dwarf blueberries next year. Blueberry crop this year is so-so due to lack of snow this year (or not as much as usual) (that's from my old plants). The farmers up here haven't started their annual harvest yet but the berries are ripening. As it looks, I think that both blueberries and raspberries can be raised successfully in containers provided they're large enough. Hopefully I'll be able to tell you how the raspberries did after this fall (if I can remember to post it).