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missti_gw

Perennials in 'raised' gardens?

18 years ago

I have a questions about "raising" garden beds.

I am in Northern Ontario - Zone 3

I presently have garden "beds" (flat on the ground level) around all three sides of my back yard fence. I am wanting to build up these gardens, planning to use cedar wood (that we have on hand) and add about 10 to 12 inches of all new soil. I presently have a mix of perennials and annuals in the gardens, so those would be removed and the new soil added.

To my questions (and...no laughing at me....) - with the soil being "above ground" (once build up is completed) does that make a difference as to what I can plant in those beds? Will perennials still survive the winter or will the roots freeze and the plants die?

I have looked all over the place for info on this...can't seem to find the answer.

Anyone? Any suggestions you have...would be greatly appreciated. I am rather new to gardening and spend a lot of time and effort - normally to be disappointed with the results.

Thank you for any input you might wish to share.

Missti

Comments (19)

  • 18 years ago

    I would think the only difference would be that roots around the perimeter of the bed would freeze a bit sooner. If you are in Zone 3, frost probably goes down in excess of three feet with no snow cover. I would mulch the beds which will help the plants adapt.

  • 18 years ago

    Yes, the outside freezes sooner and harder. I've heard of people in zone 5 putting hard insulation on the inside of the wood, or reserving the area closest to the perimeter for annuals.

  • 18 years ago

    I have a concrete retaining wall 4 feet high, with a west exposure, butting up to an asphalt driveway. Kinda tough conditions. Things that survived last year: fall-blooming aster, 4 out of 6 blue clip campanulas, sedum, hens and chicks, evening primrose, creeping jenny, purple coneflower (this was an accident!), perennial geranium. I had tried a strawberry bed with the runners going over the side, but the plants on the edge of the bed froze out. Last year was a particularly tough year as we had virtually no snow cover until late February and I had not mulched because I generally have LOTS of snow mulch. All of the plants are spaced 4-6 inches away from the edge. The edge is a good spot for sweet alyssum. Basket of Gold alyssum and some columbine survived a few years, although they are generally short-lived around here. Also, this year I replaced all of the strawberries and am trying a few scabiosa, cheddar pinks, flax. Further into the bed, just about anything survives--blueberries, delphinium, heliopsis, grape vine, etc. I replaced all of the soil with very good top soil and the area drains very well.

    At a different site, I had a landscape-timbered, tiered bed. I grew some ground cover roses for many years there, also ferns and other shady ground cover plants, relatively successfully.

    Plants that are listed as hardy rock garden plants would probably be good choices.

  • 18 years ago

    Pickering Roses in Canada advises against planting in raised beds for that reason. If you go ahead, be sure you use very hardy plants. Another consideration, raised beds need a lot more water. Mix organics into your soil to try to keep some moisture in the upper layers or you will be watering often. For me that's a deal breaker. Just some things to consider.

  • 18 years ago

    I don't know what kind of soil you have or where you plan on getting it from, but if I had to do my raised beds over again, I would NOT buy all topsoil. I would buy half compost and half topsoil. The topsoil at the dealer's yard looked nice and dark and crumbly compared to my native clay, but that must have been because it was newly dug up and therefore aerated. After a year it was as hard-packed and solid as what was already there.

    Get the best, most organic soil you can find/afford.

  • 18 years ago

    Thank you all for your input - great info here.

    Hoghaven...I see you are in Duluth - I am just across the border in Thunder Bay!! I LOVE Duluth!! Sounds like you did pretty good in your garden...I don't know many people who don't loose a few plants each year. This year - many people here had entire gardens wiped out with the February freeze that hit so hard - with no snow on the ground at the time!! It was brutal.

    I stopped by a local greenhouse at lunchtime and spoke with the owner there - she stated similar to a post above....if I stick with Zone 3's and I mulch - I should be fine - but if I am pushing for Zone 4 plants (which many people DO here) that I need to be sure to plant them farther to the back of the garden. I will stick with the Zone 3 hardier plants...and not push my luck. I don't mind adding a few annuals toward the front for colour if needed (if I don't find some hardy plants with color for the front).

    Thanks also for the input about top soil - we did the same thing here three summers ago when I put in the little front garden - the soil looked great - it is now as hard as my head (which I have been told...is rather hard LOL) and tough to do anything with. I will be moving some of that soil outta there - to the back garden when we redo the back, and do some modification to the front at the same time.

    I asked that soil question at the green house today - they suggested the top soil THEY sell at 2/3 - mixed 1/3 with Peat Moss. To add some bone meal and fertilizer as we put the soil in....and let it sit (after a good watering) for 48 hours before putting the plants back in. So..that is a bit of info for me...I was also thinking of getting SOME bags of good soil and mixing that into the area as well. Will do more reading on that.

    Thanks again for all the input. Will keep checking in for anything else people are willing to share / warn me about.

    Missti

  • 18 years ago

    Hi,

    I raised a whole border, not a lot but I put a whole row of large rocks along the edge and filled in behind them with my own compost. It is working out very well. I have clay/loam that is not too bad, but some varieties don't like it. Salvias for one are doing better in the raised border and dianthus along the edge. I also have a carex buchanii grass that is borderline hardy here and it surprised me when it came back this year.

    pm2

  • 18 years ago

    I have heard that anything in a pot gets about two zones colder in the winter than anything in the ground. I would think it would be the same rule for a raised bed. Unless you can find perennials that would stand a zone 1 winter, I don't think anything would come back. You could always buy bulbs and lift them in the fall. Good luck with your garden. -Jessica

  • 18 years ago

    Just out of curiosity, can I ask why you want to raise the beds you currently have?

    :)
    Dee

  • 18 years ago

    Missti, I am also in Thunder Bay. I know what you mean by getting your perennials wiped out from lack of snow cover. How high are you planning to raise your beds? Mine are slightly raised or at least they look it from having the dug edge and now with the mulch on top, they are definitely higher than the surrounding land. I have one island in the front lawn that is quite a bit higher due to starting it as a lasagna bed. Since it is down by the street, it gets lots of snow cover and I only lost a coneflower in that bed. Everything else came through fine. This year, I did plant sedums and hens and chicks on the edges as I find they dry rather quickly. Overall, with decent snow cover, hardiness hasn't been a problem in my beds. I do tend to plant back a foot or so from the edge. Here are a few pictures to help you visualize the beds.

    {{gwi:255088}}

    {{gwi:255089}}

    You can see the difference between the backyard beds which are new planted and the established island bed.
    Danni

  • 18 years ago

    Greetings Thunder Bay gardeners,

    When you get your topsoil, you will have to be careful to buy what you want. I had a landscaping company deliver a load (dump truck size) of topsoil. I got the bill and paid it. A few weeks later, I decided I wanted another load. When I got the bill it was about $50 more. I called and asked them if there had been some mistake. They said "no, it is correctÂone load was Minnesota topsoil and the second load was Wisconsin topsoil." They also told me that "master gardeners" preferred Wisconsin topsoil. I know I am not a master gardener (more of a trial-and-error gardener), and decided they must think I recently fell off the compost pile.

    Well, I considered this and thought about telling them to come back and pick up their Wisconsin topsoil, but garden fever was hitting, so I kept it. I hate to admit it, but the Wisconsin topsoil IS better. Not much, but better. Probably more peat and organics in it, (although, not an earthworm to be found.) After a year of adding compost and leaves, the soil now has a bunch of nice, happy earthworms.

    Hmmm, I wonder if there is a difference between Canadian and American topsoil? I hope to visit Thunder Bay soon and find out. From your pics, I guess you have pretty good soil!

    a

  • 18 years ago

    The soil around my house is pretty good although it has its fair share of clay. The area that I live in used to be a swamp which was drained for housing. I find that things grow quite well although I do have to keep up with the organic matter. The mulch you see is from an arborist who sells it for a very reasonable price ($65 for 8 cubic yards compared to $35 a cubic yard from a local landscape garden centre). Different areas of Thunder Bay have much different soil. Some are dealing with a lot of gravel type of soil and others have red clay. Still others are gardening on top of bedrock. I think I lucked out with my soil.

    Danni

  • 18 years ago

    If you are in Thunder Bay, I hope you know Sharon and Rob Illingsworth.

  • 18 years ago

    The only Illingsworth I know is a lawyer....he took care of the house details when we bought it 25 years ago. I don't remember what his first name was.

    Danni

  • 18 years ago

    Thanks again for the input...this is great!

    Diggerdee - to answer your question as to why I want to raise the beds...there are a few reasons...
    - I have two small dogs - who, if I don't have "fences" up around the entire gardens, will tromp through and find a cool spot to lay down (little darlin's) - so by raising them, and framing in wood - I can get rid of those pain the the butt fences and keep the lawn trimmed nicely up to the wood framing.

    Another reason is - the soil is very poor - we did attempt to ammend the soil somewhat - but one area was previously an "in ground" sandbox (previous owners) therefore that corner of the yard would need to be totally dug out and hauled away to get rid of that sand. Along the other side - the soil is nearly mud when wet - and anything I plant struggles there - like the roots are just suffocating.

    In speaking with other people - it was thought to be easier to add new soil on top of this area than to remove it all and start again.

    Raising to keep the dogs out will also be a huge improvement - plus the look will be nicer (I think...).

    DANNIE - your gardens are absolutely beautiful! Thank you for sharing!!

    I was trying hard to identify which area you reside in...could even leave a clue for me could ya? LOL
    I am near Vickers Park in FW - larger home (long from front to back) on a narrow lot - so the yard area is rather small. We are removing the back porch and deck in September, replacing only with a ground level deck and new garden areas - so we gain some yard space with this change.

    Gonna be a busy fall and spring here.

    Anyone bored looking for something to do?? LOL

    Thanks again everyone...the input is very helpful.

    OH Dannie....drop over with your shovel and green thumb anytime! :-)

  • 18 years ago

    Thanks missti. I was wondering if soil amendment was the only reason you wanted to raise them, in which case I was going to suggest trying another way. But if you need to keep pets out, then either raising or fencing seems to be your best options - and since you want to remove your fencing, I guess raised beds are the way to go!

    I have to say I love my raised beds. I have some *really* raised beds (cinderblock - not pretty but very functional) and some beds that are slightly raised due to being made by the lasagna method. It took me awhile to get used to the look, but now I like that definition, and I find it easier to work in that soil. But I'm a couple zones warmer than you, so I can't really give advice or an answer to your question (although I've wondered the same thing here in zone 6! So far so good during the winter - again, milder than yours, I'm sure!)

    But I can wish you luck! And I do!
    :)
    Dee

  • 18 years ago

    I have a raised bed that starts at about 3" above grade in the front, but in the back is about 30" high. I have hosta, asters, digitalis, bulbs, peonies, clematis, a pieris, a buddleia Royal Robe, pulmonaria, Rudbeckia, kniphofia, astilbes, tricyrtis, and anemone planted right at the edge that has to be mighty cold in winter. Have never lost a plant out the ones along the back edge. And the chipmunks like to dig in there during winter also.
    I am always curious as to why that bed is at least 2 weeks later than anywhere else, when everyone says that raising a bed allows it to warm up faster in spring - doesn't work that way with this bed.
    One thing to take into account is how protected the location is from wind.

    On the subject of that soil mix that is 1/3 peat - I would not do that. Peat moss will break down in 1 or 2 years and then all you have is compacted soil. It also has no nutritional value whatsoever - its really a soil conditioner that can help temporarily loosen clay soils. But once it breaks down it leaves you right where you started. I don't know how much material you need but Tracy diSabato-Aust discusses this in detail in her book the Well Tended Perennial Garden. She adds about 20% organics and tills to a depth of about 10". If you can buy mushroom compost, aged manure of any kind, leaf compost, SweetPeet, etc in bulk that will work. If I work in a smaller space I buy bags of composted cow manure or composted manure mixed with wood chips. We have a lot of horses in the area and anybody would give you free manure if you have a place to let it lay for a year or 2.

    I think topsoil varies by the load as it is typically stripped off a construction site and then mixed with something to add organic material. I had 5 yards of beautiful dark topsoil delivered 2 years ago, and today it is nothing but white clay that gets hard and was full of field weedseeds. And that was a reputable supplier too. I found out later they made a mix of 1/3 topsoil that was probably garbage, 1/3 sand, and 1/3 leaf compost. Looked great till the leaf compost deteriorated and I'm left with nutritionless white clay.

  • 18 years ago

    Aww geez you guys...just when I "think" I know what I am doing...ya go throw me another curve...

    I need more info on soil now...what does "organics" mean ??

    alyrics (message above) mentions the issues of the soil mixed with peat turning hard and crappy in a few years (my term)...which is where I am now - I do NOT want to be here again in a few years.

    So...top soil...mixed with organics or mushroom compost???
    Are these all bought in bags? Go ahead...you can laugh...I know ya wanna.

    Maybe I should go with plastic flowers from the Dollar store and then I don't have to think so hard?? LOL

    What is the best mix? Does it depend on what I am going to plant?

    Keep posting please....you folks are smarter than I will ever be on this subject and I truly appreciate the input here.

  • 18 years ago

    Missti -

    Your questions really aren't silly - we all started where you are and learned from other gardeners. My husband always says (quoting his mom) that the only dumb question is the one you didn't ask!

    Organics will be material largely from plants - leaves, manure (since much of the celulose in plants goes through the digestive system of horses, cows, etc without too much change), grass clippings, coffee grounds, etc. You can get bagged organics at garden supply places, but you may also have bulk local sources that may be free (if you are willing to load and haul yourself,) or inexpensive. I've heard of folks who live in cities asking the local coffee place if they can pick up their used coffee grounds. Around here we get a mix of sawdust (used for horse bedding) and horse manure from one of our neighbors who has horses, or the local dairy farm will deliver a huge truckload of fresh manure (which your neighbors might not appreciate if you have an in-town lot!) The next town over has a municipal composting program; they collect leaves and grass clippings and such, compost it, and offer it free or inexpensively for residents if you come to their storage area with a pickup truck or large containers like garbage cans. The local power company hires someone to cut and chip branches that are endangering lines, and we have found that the tree guys will usually drop off a load or two or five if we ask nicely and no one else has asked first. I also can get wet sawdust from the local sawmill or wood shavings from a shop. Any of these can be mixed into your local soil to add organics and improve your soil texture. If you use uncomposted materials like wood chips, sawdust, or wood shavings you need to add a reasonable amount of nitrogen, mixed into the soil as well, since the process of decompsition uses nitrogen and your plants will end up suffering from too little available nitrogen for their own growth. (Some people say never to use wood chip type materials, but I've been doing it for years successfully. You just need to be sure to avoid walnut wood products and add lots of nitrogen.)

    For future use you can also make your own compost from your own leaves and grass clippings as well as kitchen scraps of any plant-based material and add it to the top of your soil - over time the worms and burrowing mammals like voles and chipmunks will mix it in for you as long as you keep adding it to the surface. For information on how to do composting, check out the FAQ on the soil, compost and mulch forum.

    Here is a link that might be useful: soil, compost and mulch forum

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