Have large bags of Miracle-Gro potting soil. Would like to use it to repot a lot of japanese maples. Should I add sand or perlite? Thank you
First, I wouldn't use it at all. Although it doesn't have a great reputation overall, it may perform perfectly well for a single season container planting, like for annuals or tomatoes and other veggies, but it is not the right stuff for any long term (longer than a single growing season) container planting and especially not for any woody planting.
What you need is a potting mix that offers some durable, coarse texture that will hold up to frequent waterings without breaking down and losing porosity. That means something with with a lot of bark to it, as well as perlite, pumice or Turface (or other high-fired clay particles). And you need something that offers a slightly acidic pH.
If you cannot find a premade mix that contains these specific types of components, you could make your own. I'd recommend Al's 5-1-1 "gritty mix", from one of the most knowledgable regular participants on the Containers forum:
5 parts pine bark fines
1 part sphagnum peat (not reed or sedge peat please)
1-2 parts perlite
garden lime (or sulfur in the case of acid lovers)
controlled release fertilizer (if preferred)
micronutrient powder, other continued source of micronutrients, or fertilizer with all minors
You might want to review previous threads on this forum that discuss growing JM's in containers for additional information or visit the Container gardening forum and ask the same question of the experts.
This is my soil mix:
1 bale 3.8 cu. ft. Pro Mix
1 bag 3. cu. ft. bark mix with peat and perlite. loose bag
4 bags 30 quart top grade top soil. I like Fafard.
2 cu. ft. supercoarse perlite.
I would caution you against to much bark in the north east. I use to sell maples to a grower in North Carolina. In the Carolinas they use a lot of bark mix, I suppose because it is cheap and goes a long way. I had picked up some of the plants one year that I had sold to this nursery and brought them back to New Jersey. At the time I was in Passaic County and tried to winter them over and lost half of them. The next spring I had to repot them and knock off all the bark mix for heavier soil. I believe that the bark soil in my area of the country dried out to much in the winter and the roots of the plant had dried froze.
where to get the ingredients?..Today I checked HD and private garden store. Perlite or some other top grade soil (no Favard can be found around) can be purchased at HD.. But they don't sell Pro-mix or bark mix with peat and perlite..
Since you are in NJ too I have another question to you: I overwinter my JM in a shed. Do you keep yours outside?
What part of New Jersey are you located in?
This is simply not going to be practical for many people who have JM's in pots. Many of these inhabit balconies, patio's, or very small yards. These simply don't have the space or the number to justify making their own potting mix. I myself have three in container's, two of these 2 gallon size, and so it does not make sense for me to try to make my own mix.
I really think you should read some of the posts regarding soil mixes on the Container forum before you begin mixing your own. Most commercial container soil mixes are soil-less and for very good reason. Any type of soil - like topsoil or garden soil - offers far too fine a particle size and therefore it retains too much water and impedes drainage. It also has insufficient pore space to allow proper oxygenation of the roots. You don't want heavy soil in a container - you want a mix that has sufficient texture, aeration, drainage and moisture holding capacity and that doesn't exist with a predominately soil-based mix, like the recipe provided above.
A mix that has a lot of bark in it IS what's needed and countless growers of containerized maples and other woody plants in all areas of the country use it with high success. Growers use it extensively not because it's necessarily cheap or "goes a long way" but because it IS a highly desirable component for a container soil mix for woody plants. Drying out during the winter is not the fault of the mix but rather lack of proper attention on the part of the grower - plants need adequate moisture in winter just as they do during the growing season. Containerized plants even more so than those in the ground as they don't have the same benefit of the vast soil mass nor a wide spreading root system. FWIW, bark fines are often sold with a label as "soil conditioner" if you have difficulty locating them as just "bark".
Arktrees, I understand what you're saying, but it is quite possible to locate the ingredients for a suitable maple container mix in smaller quantities - some of the ingredients are the same as those sold for houseplants or bonsai and should be available in quite small sizes. They are in stores and nurseries in my area :-) And any extra can be stored for future use. You can also locate better commercially prepared, bagged container soil than MiracleGro too, but it may take some looking. The alternative is to find a good soil-less container mix and add the necessary additional texture to it.
This therory might work in you area but I will ask you to walk a mile in my shoes. Soilless mixes will not work in this area. I don't care how much you pay attention to watering in the winter. The ground is frozen and water will not seep in the soil of the container but the soil is drying out none the less. I also know a few growers myself and the ones that I know in the norther parts are switching back to top soil in their mix. Approx. 30%. Oregon plants coming to the east coast from my experience, will have a 50% dead rate on the first year and the second another 50% and the next on and on till they no longer exist. If I buy an Oregon plant I will shake all the soil of the roots and repot so that they will survive our winters.
I suggested Fafard top soil because it is not a heavy top soil but loamy. Yes it does hold the nutrients far longer then soil less mixes which I like.
Now I don't profess to know everything for no one knows everything. I am still learning. I am only 8 generation in this family business and 50 years of my own on the the job training. Maybe the next 50 years I will learn some more.
Now these are my opions on what I have found works for me. I would suggest for people to do what they feel is right for them.
Bark is the way to go.
For those with only a few containers to fill, even more reason to mix your own.
If you've absolutely convinced yourself that planting mix should be "brown" like
dirt, then simply add in screened pine/fir bark fines which will satisfy the
need for a dark, "soil-like" look, while also increasing the moisture content of
I am in Denville, NJ
Dave, it is a matter of understanding the science of soils and how that applies to containers. They present very specific growing requirements for success and the majority of those that do this professionally, as well as many hobby growers, recognize the importance of a correct soil mix and are virtually unanimous in their opinions - based on the science - that a soil-based mix is not going to offer the same kind of positive long term results as will a soil-less, very textural bark-based mix. I fail to see why location has any bearing on the type of container medium used and I have a difficult time accepting just anecdotal evidence as a valid explanation. There are a great many containerized maples shipped from Oregon and other west coast locations - they account for the majority of JM's grown and sold in this country - and it is highly unlikely they all experience the rate of failure you describe. The market would collapse :-) I am going to have to assume your experience is due to other issues, perhaps lack of acclimatization or other aftercare.
I am glad you have had success with your methods but I'm going to tell you that you are the exception to the rule :-) And I would caution against advising others to follow your methods without doing their own research into the specifics of growing JM's (or any other woody plant, for that matter) in containers.
I've invited the comments of one of the most knowledgeable posters on the Containers forum - his experience is extensive and he has done a lot of research onto this subject and will be able to explain the details far better than I. I hope he will respond.
Are you saying that the experience of 7 generations before me was not enough time to form an opinion on the subject. I will tell you that I have grafted more plants and potted more plants then most experts in the field. Mater of fact we supplied Iseli's nursery back in the early 80's. His order was over 45,000 grafts on the trailer. All together the grafting season consisted of approx. 450,000 grafts a year and then came the potting. If after all that potting of plants and I haven't found the right soil, and all this time was only for anecdotal reasons, then I have failed. Like I have stated before these plants dry freeze. It is just like food wrapped in freezer paper placed in the freezer for months. Take it out and what you have is freezer burn. I am just happy that my plants do not know about the science of potting soil.
I remain of the opinion that the majority of those that end up passing through this forum simply will not be mixing their own. Some will be discouraged and give their maples away to someone that mostly will take even less care to find out how to care for them. Others will simply continue to do what they do. Only a small percentage will be ardent enough to undertake such an effort and added expense as to make their own. That is simply how people as a whole are. I hope to be able to eventually plant mine in the ground, but a couple years of late freeze, immature larger species of tree, and several other events have caused me to go mostly the container route for the time being. So the question I would pose to all of you would be What would you say the best commonly available container soil for JM's. And yes cost will be a consideration for those that fit this group. Very few of these will be willing to pay $20+/CF, plus the non small cost of transport because it is not available locally. Just some thoughts to consider.
I think that blaming the soil because it dried out during the winter is like blaming your car because it ran out of gas. You do have an obligation, and it makes good sense, to ensure that neither happens. ;o) If you choose only soils that won't dry out during the winter, they'll be too water retentive during the active part of the growth cycle.
Arktrees - you're making some assumptions that won't hold water. Most growers of any particular type of tree are more than willing to go to a little extra effort to build a soil they know will specifically fits their growing habits and their tree's needs. As far as the expense, soils made from your (small) bulk supply of ingredients that are purchased in larger bags or by the cu ft are, in most cases, less than half the cost of commercially prepared, bagged soils.
I agree with Pam and Josh. Most, if not all, of the arguments used above against soilless mixes for hobby growers are easily dispelled. A soilless mix of durable materials that will retain its structure from repot to repot is the only way to go if your wish is to have your trees growing at anywhere near their potential genetic vigor.
Excellent growth and root health can be had starting with a simple basic mix of pine bark, peat, and perlite with dolomite + an appropriate nutritional program, or a mix of equal parts of pine bark, Turface, and crushed granite + a little gypsum. I've grown thousands of perfectly healthy plantings in these mixes over the course of many years. ;o)
Gardengal, you're quite presumptuous in your comments to Dave. I was going to paste in an example but the whole first paragraph sounds condescending to my ears.
Al, I believe your analogy gas::water is mistaken. It's not practical to actively manage moisture level in pots through winter in N.NJ or even in S.E.PA. I agree with Dave that the mix should hold sufficient moisture to sustain the frozen pot through the season.
"soils that won't dry out during the winter, they'll be too water retentive during the active part of the growth cycle." seriously where did you dig that one up? Al, that generalization doesn't hold water.
The question of adding soil to a potting mix doesn't get explored and discussed when dogmatic replies based on limited regional experience reign.
The sandy loam in my S.NJ adds biology, moisture retention, pot stability and texture to the Organic Mechanics soiless mix i use for potted trees.
Here is a link that might be useful: Potting Media
I think the analogy rings rather true. If you have trees you're over-wintering, they may need to be watered or have a little snow thrown on them from time to time to keep them viable. You also need to make a little effort to add the gasoline that makes your car drivable. Darn close, I'd say. ;o)
I overwinter around 150 trees, more than half are deciduous, and a good number of those are Acers. I grow woody material in a mix of Turface, crushed granite, and pine or fir bark. I add a little gypsum to the mix for Ca/S, and include a little MgSO4 in the fertilizer solution to provide Mg and keep the Ca:Mg ratio in a favorable balance. I then use either MG 24-8-16, 12-4-8, or Dyna-Gro's Foliage-Pro 9-3-6 (3:1:2 ratio fertilizers, all).
The soil is free-draining, well-aerated, and holds water/nutrients well. Root health is superb and growth is superior to any peat-based soil I've used & the soils with any significant mineral-soil presence (topsoil, loam, garden soil ..... what ever you might wish to call it).
I'm not sure how anyone can make the assumption that a soil like this won't work because of regional differences (dogma). I actively manage container moisture levels in my (200+)containers over winter - how much different is MI from PA or the NE? The soil is quickly adjustable for water retention simply by increasing the Turface and reducing the granite for more water retention, or reducing Turface and increasing granite for less.
We're talking primarily to hobby growers, and I KNOW these people. If you show them a soil that will out-perform the bagged, commercially prepared soils and a few hundred people come along to praise it and confirm how well it works after they themselves have made the change, they will go to what little effort it takes to locate the ingredients and build it.
The problem here is, I am arguing from the prospective of the plant - what is best for it and what willl keep it growing at it's potential genetic vigor, and you guys are arguing from the perspective of what is convenient for you. I'm often at odds with growers who support a practice out of convenience or a necessity based on ideological cultural limits they have either placed on themselves or that they must work within. It's very often you'll find me saying that grower convenience and maintaining optimum plant vitality are more than occasionally at odds with each other and often mutually exclusive.
BTW - there is nothing dogmatic about me. I have an extremely open mind and am very flexible in my approach to all forms of gardening. If you want to explore mineral-based soils for container culture - state your case and we'll discuss them. I'm very familiar with the pro/con arguments.
Well Al, I disagree, and that's fine. First we are not talking about "growers", we are talking about something that has a million other things to worry about in their lives other than being a JM "grower". When you can't even get people to read the labels on the fertilizer bags etc for their lawn (which they often see as more valuable than trees anyway), I really don't expect that the great majority of people will go to a great extra effort/or extra expense. In addition many people do not have such things available to them within a reasonable distance (as was the case for my own rural upbringing), and/or don't really know how to get it in a cost effective way. All you need to do is look at the other forums of how people fail to grasp even basics Add to this that frankly some of the advice I have seen given by "those in the know" or "experts" of a forum is just so much horse fertilizer. Much of it is simply not scientifically valid (and yes I have a science background FWIW), or ignores basically biology.
To assume that most everyone will see their JM's as their cherished babies is simply not true. Most will not. It happens with any kind of pet or whatever no matter the cost. How many homes have you seen that are absolutely neglected for no reason? Hint, there are an awful lot.
So to provide whatever help is possible to those that are/willing to make some effort to look for information, but may not be able/will not go beyond maybe adding occasional fertilizer, re potting, or maybe add some perlite into a potting mix, what would be the way to go. What commonly available potting mix would be most suitable to start with?
I'm a hobby grower - I just have a bunch of trees - too many, in fact. ;o)
Now we're starting to separate the wheat from the chaff. I'm perfectly willing to allow that prioritizing is a major factor on the forums, and I'm not trying to get anyone to change their priorities and set their trees above all. What I DO want to accomplish is letting people know there are much better, and less expensive alternatives to commercially prepared and bagged soils. I'm ready and willing to stand in the trenches & argue my points from the perspectives of practicality and science. (Next said with a smile - actually, I'm feeling pretty good-natured about this conversation) So if you think I'm full of fertilizer, I'll at least be able to understand when shown the error of my ways when someone points them out. ;o)
At any rate .... I'm not interested in the people who don't have at least SOME passion about their growing experience. I'm perfectly willing to let them go their own way and use whatever soil they prefer for what ever reason. There is no use whatever trying to help people who do not want to help themselves, and I recognize that. You cannot push anyone up a ladder unless he is willing to climb himself. The people I care about are the ones who want to increase what pleasure/enjoyment and satisfaction they take from growing and aren't reluctant to make a little effort to accomplish that goal. SO .... when I, Pam or Josh tell Merchela that MG is a poor choice and outline a better alternative, we're reaching the whole forum and still allowing Merchela to consider and accept/reject the offering.
I'm not willing to assume that everyone who reads these words is lazy and uncommitted to growing. I KNOW that's not true, because I talk to excited, enthusiastic people every day @ GW. I WISH you could read my email. ;o) So I'm going to make my best recommendations & let whoever is interested weigh their substance. If I get disagreed with along the way - so be it. I promise I won't allow myself to enjoy the comfort of opinion without the discomfort of thought..
Marchela - If you are going to use the MG soil, I would mix it with a substantial volume of fine pine bark and a lesser volume of perlite (5 pine bark fines: 1 MG Potting Soil: 1 perlite + garden lime). BTW - this will also be MUCH less expensive than buying the MG soil.
Sorry that it sounded like I may have been talking about you and horse fertilizer, that was not intend, and that was due to how I wrote my reply. You SEEM to be horse fertilizer free. Also said with a smile. :-) What you have written has not struck me as being unsound, and that you are willing to listen speaks well of you. That frequently is not the case. These forums, and forums in general, often arrive to a group opinion that may or may not be valid, and is frequently resistant to incorporating anything that contradicts that opinion. I'm sure there are many people that I am not on their rosy rosy he's a great guy list. I'm good with that. :-)
I was making a point that not everyone is equal, and that many will not stay on the forum, and many more will never register to post. They do have some "passion" as they are looking, but maybe it is limited now, but could grow (I'm sure you didn't start out with 200 containers). I would still like to provide some help to these person's, and that was my goal. Thank you for your help for those that just might have to use MG or similar.
As far as to where you stop point of being concerned about what others do, I have to agree that you can't make them help themselves. But those that will find this discussion, are trying to help themselves, but just may not be able to do significant;y different (for whatever reason) than what you posted below. This being my own stop point BTW. :-)
Hope all is well for you, and your growing season is a good one. Spring is breaking out here (even thought it snowing and 33F at the moment), and everything is looking greener in my yard. Grass is definitely NOT greener on the other side.
I wish everyone I argued against was as gentlemanly as you've been. Temp dropping here - freezing rain and snow through tomo night. Did about a dozen deciduous repots on the driveway today and the temperature dropped 20* or more while I worked. Brrrr! Lawns just greening up a touch. Forsythia's blooming still a couple of weeks away.
Arktrees, just by virtue of taking the time to post the question here or to inquire as to the suitability of the MG mix would lead me to believe that the poster is indeed interested in the welfare of their containered maples and is willing to take the time and effort to ensure their success. To offer the suggestion that there are much better alternatives than 95% of the premixes on the market and to provide info regarding what is best included in these alteratives is a logical response. The "great majority" that don't have this as a high priority or can't be bothered even to ask are unlikely to visit this forum and read this thread anyway :-)
If I am understanding your point, you are asking what is the best packaged mix you can get easily and inexpensively that will work for containerized JM's. And I think what we are collectively replying is that if you have to travel any distance to obtain potting soil in the first place, it should be just as easy to obtain some additives, like the bark fines or ground bark and perlite/pumice, that will vastly improve the performance of most packaged mixes, exactly like the last piece of advice Al left for Marchela. If not all the ingredients necessary to make your own. Walmart sells bark and perlite, as does HD and Lowe's and I should imagine so do a lot of more regional hardware/home improvement stores. And neither of those additives are pricey. Buy the smallest sizes they have available, mix in the correct proportions and you're good to go. Al may not agree 100%, but I've found even larger bark sizes can work quite efficiently, as long as they are not too large.
If you are remote enough that you have to mail order in even just potting soil, I don't know what to tell you ;-) Shipping costs are huge relative to the cost of the material. I thought folks were nuts when they mail ordered a very superior grade (and not inexpensive) potting soil designed for woody plants from my nursery and paid 2-3 times the cost of the product in shipping charges but I understand there may be areas where these commodities are hard to come by. Surf the 'net and find the nearest and least expensive source and hope for the best. Repotting annually might be advised or get them into the ground as soon as possible.
I'm with Al. I've learned a great deal about growing plants in the container. Needless to say, my tree seedlings grew better. My mix may be different than Al's. Mine looks like this because of extended hot weather that required more water. I tried 5-1-1 and it seemed to last rather short before I could water again even in the same day when it gets very hot.
3 parts pine bark fines
1 part expanded shale (much more available than Turface around here)
1 part peat moss (MUST find one with wettable type)
Not sure if I ever needed garden lime since I sit on top of limestone bedrock and the water source may be enriched with it???
They do fine except taxodium (cypress) trees that seem to need more water... Oak seedlings and shantung maple seedlings do fine. I just don't know what to do with that many seedlings...
I've read all of this and it's confusing! I posted earlier today with pics of my JM. The leaves are brown and crispy at the edges. It's in a ceramic pot and in MiracleGro dirt, morning sun/afternoon shade. GardenGal thankfully responded that the problem was likely the MG dirt (who knew that stuff was so bad!). Anyway, I'm going to repot - today, before it gets worse. I'm not willing to wait until the tree is dormant and since it's in a pot now, I don't think I'll do any damage. To get to the point, I'm heading to Lowes. As far as I can tell from all the above posts, there is nothing premixed commercially and I'm sure I haven't seen any premixed soil for JM at our Lowes. Tell me if this is a good plan:
Pine Bark (only kind they have is "pine bark mulch" - will that do?
Do I need perlite?
I know this probably isn't perfect, but is it okay? Our area is very limited in available options at our Lowes.
If you are reading this, you are seeking information. That is always a good step in the 'greener' direction.
I'm growing some conifers in containers and having very good success. The same basic rules that I use for pine, spruce and fir trees will work for your maples or other woody plants.
Basically you need to supply moisture, nutrients, and oxygen to your tree while at the same time providing good drainage. (Good drainage helps avoid root rot, a very common problem with container grown plants.)
MG or similar brand bagged soil is mostly made up of peat with some perlite and other stuff mixed in. While it DOES hold moisture for the tree roots, there are two big drawbacks:
- peat-based soil drains poorly and stays wet a long time, especially near the bottom of the container where the roots live, increasing the chances of root rot
- peat-based soil compacts over time, restricting the amount of oxygen getting to the roots
By reading posts in the Container Gardening fourm I've found that a much better soil mix can be made for trees and other woody plants, and generally at a cheaper price than the pre-bagged MG soils if you buy your materials in quantity or when on sale.
You should read the posts in the Container Gardening forum for all the details, but basically a good container soil for trees is approximately 1/3 pine bark, 1/3 Turface, and 1/3 granite. This mix is called the "gritty mix" and holds enough water for the tree but also provides adequate oxygen and drainage at the root level.
If you use this formula and adjust it to meet the needs of your trees, you will have a much happier tree and notice faster growth. I've noticed a big difference in the growth of my container-grown conifers compared to regular garden soil or pre-bagged, peat-based soils like MG.
I use a similar gritty mix for my maples.
One part pine/fir bark, One part pumice, and One part perlite.
Occasionally, I'll add in gravel, which holds very little moisture,
but provides excellent structure.
Josh, that sounds like a good soil. If your container soil holds enough water and nutrients, drains well, and provides oxygen to the roots, your trees will be very happy. Remember, most trees don't like wet, soggy roots.
If you use regular garden soil or peat-based soils like MG, you'll eventually have a soggy mess on your hands. You might get away with this in a short term planting (a few months perhaps) but for growing trees containers you really should try a gritty mix like Josh is using.
If your tree needs a bit more moisture simply increase the amount of bark or Turface, both of which hold water. If your tree requires less moisture, then add more granite/gravel and cut back on the Turface and bark.