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kristimama

Best Potting Media/Planting Mix for Large Containers

kristimama
12 years ago

Hi Everyone,

I am wondering, for those of you who do grow any of your roses in containers on a semi-permanent basis, what is the best potting mix for them? Do you use one of Al's 5-1-1 container mixes, or some variation, or something else entirely?

I grow a LOT of things in containers (citrus trees, veggies, salvias) because I have an enormous concrete patio with a grey concrete block retaining wall off my main living space and I'm always looking for ways to break up the grey. I adjust my planting mixes based on what I'm growing... I'm just wondering what works best for roses.

I have a couple 1/2 wine barrels and a couple large (i.e. 24" round, say 20 gallon) pots I'm planning on using for roses.

I know these won't be permanent plantings, but I'd like to get 5-6 years out of them if possible.

Thanks!

Comments (16)

  • jeffcat
    12 years ago

    I typically just use Scott's or Miracle Gro "Moisture Control" Potting Mix. It already has a lot of peat in it so it retains moisture better which is the biggest culprit with potted plants losing moisture easily. I've never had problems with it. I tend to amend about 3/4 cup of Rosetone in with the soil in the big containers and then about a month or two later depending on the rose, I mostly liquid fertilize from there.

  • strawchicago z5
    12 years ago

    If you have alkaline water, MiracleGro potting soil in the green bag is the most acidic, pH of 6.5 and stays acidic for more than 1 year. However, this has too much peat moss and doesn't drain well. My hubby had just drilled holes at the SIDES of my pots, about 1/2" above ground. The holes at the bottom won't drain, if it sits on cement or heavy clay. You would have to elevate them with bricks, to leave the holes open.

    I tested the green-bag MiracleGro potting soil versus the brown-bag Organic MiracleGro potting soil. Many praised this Organic potting soil. The Organic one drained twice faster than the green bag of regular MiracleGro potting soil.

    I'm amazed at the over 1 foot tall with buds BANDS that I received from Burlington Roses. Upon checking the bottom of these 5" tall bands, it's 90% openned! Compared that to the tiny holes of the bottom of my pots - so I enlarged the holes more. People in the container forum reported that Tapla's recipe of 5-1-1 (5 parts fine bark mulch, 1 part peatmoss, 1 part perlite) perform better than MiracleGro's. The soil in the pots at HomeDepo, or the bands that I received are fluffy, mostly fine barks - compared that to the dense, mostly peatmoss of MiracleGro's green bag. If you can get a bag of fine barks and mix that with MG's green bag for better drainage, then add some garden soil for beneficial bacteria, that's great.

    Even with my alkaline water, the roses in the pots with Organic MiracleGro potting soil are doing MUCH-BETTER than the pots with the dense, mostly peat moss green MiracleGro potting bag. These pots are perpetually wet, there's whiteflies and blackspots on these newly planted band-roses. Hopefully they improve after drilling extra holes, and mulched with horse manure. I was looking at the indoor houseplants at my doctor's office. The pot with really dry soil on top has 100% healthy plant. The other pot with wet soil is sick-looking with plant diseases.

  • strawchicago z5
    12 years ago

    Someone wrote a blog blasting the green bag MiracleGro potting soil, and suggested Scott's instead, since has larger chunks mulch for better drainage. I am biased and like everything that has Scott's logo, including lawn fertilizer.

    It really depends on one's climate. If a person lives in a blasting heat summer, full-sun, with little rain - MiracleGro moisture control as Jeff suggested is a good choice so one doesn't have to water often. However, other folks gave this "Moisture-Control" a big thumb down. This includes me, who lives in a cooler summer, heavy rain with flash flood, and a shady garden.

  • strawchicago z5
    12 years ago

    Sorry, I had my mind fixated on Scotts - here's the correction: that person's blog recommended Schultz, with chunks of bark for better drainage. When I checked on "Moisture-Control" potting soil, there are too many people gave it a thumb-down, that's why I didn't buy it. I'll take frequent watering of my pots over diseases any time.

  • strawchicago z5
    12 years ago

    I have just checked my 14 band-size roses: the 3 in regular MiracleGro potting soil (most acidic) came down with fungal diseases: 2 blackspots, and one mildew, all have whiteflies hovering above the perpetually wet soil. The 10 in Organic MiracleGro potting soil, less acidic, better drainage, don't have diseases.

    The most healthy and vigorous one is Paul Neyron, planted in my limestone and dolomitic soil. Since he's tall I could planted him 2 to 4" deeper than soil level for winter survival. He is 100% healthy, not a speck of disease, and get the least sun compared to other 13 roses in pots. Alkalinity in soil discourages fungal diseases. I would aim for neutral, rather than acidic potting soil, and mulch with alkaline horse manure if diseases is an issue.

  • organic_tosca
    12 years ago

    I use Black Gold in my pots, and my roses seem happy with it. The only real problems they have are light/sun exposure and insects, but nothing seeming to do with the soil. They all look healthy and and are starting to bloom now, with lots of buds. I was previously using Maxsea to fertilize them, but earlier this year, when they were all looking a little peaked, I gave them some Osmocote and laid on some good mulch, and they have responded quite well. I haven't decided whether or not to continue with the Maxsea.

    Laura

  • strawchicago z5
    12 years ago

    Thank you, Laura, for mentioning Black Gold. I heard many good things about it. Unfortunately it's available in the west coast, but not my Chicagoland area. Fine Gardening Magazine has a good article on how to make your own potting soil, and what's the best potting soil brand by region. Blackgold is listed as BEST for the West coast.

    The recipe that Fine Gardening Magazine listed is: 1 part peat moss, 1 part perlite, 1 part compost, 1 part garden soil. Optional: some lime, soybean meal, rock phosphate, and kelp meal. I already ordered potting soil from a nursery here. Its recipe is similar to Tapla's (5-1-1). I'll test its performance on roses compared to Organic MiracleGro potting soil.

    See below for Fine Gardening's Rating of Potting Soil by Regions:

    Here is a link that might be useful: Fine Gardening Magazine rating of potting soil

  • organic_tosca
    12 years ago

    Strawberry - I'm glad to hear your info on Black Gold. I always thought I would like to try Tapla's recipe, but I just am not up to that. But I'm sure it's good. I really don't know much of anything about soils, which is why I got the Black Gold - one of the VERY knowledgeable posters on this forum said it was what she used in containers. I'm really pretty new to all this.

    And a big Thank You for the link to the Fine Gardening Mag ratings!
    Keep us posted on how your potting goes!

    Laura

  • strawchicago z5
    12 years ago

    Hi Laura: As Jacqueline, Tessie, and JeriJen often said: "location, location ...." Tapla's recipe of 5 parts fine mulch, 1 part peat moss, 1 part perlite is best for climate like mine: low-sun, flash flood warning and fast drainage is a must.

    It is recommended by Douglas Green, an owner of a large Ontario nursery of many plants in pots, including roses. If I use Al's 5-1-1, there is no need to put loose gravels or bark nuggets at the bottom for fast drainage. However, I use super-slow draining MiracleGro in green bag, and medium-slow draining Organic MiracleGro. I skipped this important process of putting loose stuff at the bottom, and regret it terribly. Now I have to dump the soil out of each pot, and start all over. I realize this after a heavy-rain simulation with a hose, with the pot flooding over and loses 1" of soil - which happens every time it rains here!

    Sure, Field Roebuck said it's not important, just put a paper towel at the bottom of the pot, and fill up with soil. His Texas climate doesn't have the low-sun, and 6" of rain flash flood.

    Each region should have its own recipe of best potting soil. Now I realize that the regular MiracleGro potting soil (green bag) might have been made for indoor pots, where one puts 1 measly cup of water per week. It's not meant for several outdoor heavy thunderstorms with 4 to 6" of rain per bout like my climate.

  • roseseek
    12 years ago

    I second the Miracle Grow Moisture Control soil suggestion. I've used it to raise my rose seeds in; for moss hanging baskets; gallon to twenty gallon cans and pots and have never had drainage issues with it, ever, period. My soil is highly alkaline and there are no chlorosis issues with it, with any kind of plant I've grown in it. I plant clients' patio pots with it because they don't have to water them as frequently and nothing has suffered since I've switched to it. The stuff is acidic enough for potted gardenias, even with our alkaline water. I haven't tried any other brand here I've been nearly as satisfied with as Miracle Grow Moisture Control. I usually pay $14.97 for a 62 qt bag at Home Depot or Lowe's. My local Costco has 55 qt bags for $9.97, so yesterday, I bought two. 62 quarts for $15 or 110 quarts for $20? No brainer. Kim

  • diane_nj 6b/7a
    12 years ago

    I third the Miracle Gro Moisture Control. I used ProMix for awhile, but I could never get it wet enough down by the roots. I don't like my pots to dry out too much between waterings.

  • strawchicago z5
    12 years ago

    I'm glad to hear Kim and Diane liking MiracleGro Moisture Control, since the reports of NOT-LIKING it comes from heavy-rain areas like Michigan and Illinois. I have been using MiracleGro in the green bag for the past 12 years with good results. Only last year, when I didn't fill the bottom of pot with loose gravels that my flowers got too wet and stunt with our 49" rain.

    I'm going to get that MiracleGro Moisture Control and try it along with loose gravels at the bottom for fast drainage in the event of heavy rain down-pour. The shape of the pot matters: the shallow ones like a bowl gets dried out fast, and MiracleGro Moisture Control would be perfect. It's the tall vase-shaped pots (very large at top, and very small at the bottom) that drains poorly with heavy rain. Those definitely needs gravels or bark nuggets for its tiny bottom.

  • roseseek
    12 years ago

    Strawberryhill, if your pots are heavy and you have to move them, Pelspan, the foam "popcorn" packaging can help do what your rocks and bark nuggets do with virtually no weight. They take forever to break down and even wet, weigh nothing. Kim

  • jeffcat
    12 years ago

    Unless you live in a tropical rainforest, I can't imagine where the soil needing drained is such a dire thing. Most of the time the rose is large enough in the pot that the majority of water misses the pot altogether. This is why fertilizers are recommended to be spread around the outside of the "drip line" on plants. The drip line on most potted roses is outside the pot which is why I use the moisture control. It takes one heck of a dousing to get the soil saturated in a large pot for me.

    On the Princess Alexandria of Kent I just potted up this past week, I just took the single drain plug out in the bottom and that was enough for me. The water will find it's way out through there if there is too much for whatever reason.

    Charles Darwin
    {{gwi:248115}}

    New Princess Alexandria of Kent(By the way, that pot is a nice resin pot that's on sale for $40 right now at Lowes)
    {{gwi:248116}}

    Golden Celebration when it was potted:
    http://www.helpmefind.com/rose/l.php?l=21.163647

    Abraham Darby when it was potted:
    http://www.helpmefind.com/rose/l.php?l=21.163047

    Bishop's Castle when it was potted:
    http://www.helpmefind.com/rose/l.php?l=21.163652

    Don't mind the spindliness on the last 3...they were young but very vigorous plants, but didn't have the "bones" to support it yet.

  • strawchicago z5
    12 years ago

    Thank you, Jeffcat for posting those great pics. Seeing your pots on the wooden deck gave me an idea to save me the hassle of fixing the drainage. My 13 pots sit on the cement patio, or on sticky clay soil. They don't drain well sitting on top of such dense material. But if I elevate them on wooden pegs, they would drain faster. Bricks are harder to work with, since they are heavy.

    My roses are tiny own-roots, band-size, and the pots have really large upper rims, designed for annuals like impatients and petunias.

  • jeffcat
    12 years ago

    I don't think it's especially important on how fast the pot drains, just more so that it does have a means of drainage when necessary. You could pour 5 gallons of water in my pots and it drains eventually if there is excess. It's not like it will lay in there for days. In probably, at the most, 30 min, it's drained from excess and usually well before then. Just my opinion, but just take the single drain plug out of the bottom or if there isn't one, just drill some 1/2" holes in the bottom. I personally don't use any rock bottoms or anything, but that's just personal preference. I just toss in soil...for me the more, the better for the root networks. I planted Golden Celebration, Abraham Darby, and Bishop's Castle into the ground from 24" pots and when I pulled them out, they had those pots pretty much filled with roots after only a year or so in pots, so I tend to value the soil. With that said, I dug up a Dr. Huey and have it just sitting in an 8" pot and it's still alive and growing, so...haha

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