Advice for a Tomato Container Garden

trailwestApril 16, 2012

A friend asked for advice for the her tomato container garden. She has two medium sized tomato plants in dark containers in the full sun on a white limestone patio.

Here is what I told her:

Pros: The plants get full sun from morning to dusk and are protected from winds by the fences. The patio reflects light and adds to the total sunlight they plants can get. The containers are large and should accomodate a full grown tomato plant. The basil is a good plant-combining touch and will complement the tomato both while growing and for making Italian food.

Cons: The plants are in dark containers which will lead to high temperature variations for the roots of the plants. An organic farmer once told me that one of the most important tricks for growing great tomatoes in very hot climates like ours is to make sure their "feet" remain at a constant temperature and that they don�t get too hot. There are many that will tell you that if the roots of tomato plant get over 70 degrees (F), the plant will not set fruit. They will grow like crazy but you will get no tomatoes.

Did I give good advice? Do you have any other tips?

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stev32k(Zone 8)

I've been growing tomatoes in containers for over 10 years now. The containers I use are 35 gallon plastic garbage cans. They are set in full sun for about 10 hours per day and the cans get very hot to the touch on the sunny side and cool on the shaded side. I've wondered about the effects of a high soil temperature, but have never seen any problems that I can attribute to soil temperature.

I usually grow two or four plants and one year I placed shade cloth around two containers and left the other two in full sun. I could not tell any difference in any of the plants. I got about the same number and weight of tomatoes from each one.

The single most important factor I've found is water. It's not just volume that's important it's also frequency. If the moisture content of the soil varies very much the tomatoes will end up with radial cracking and cat facing. I now have a system set up that waters each plant every four hours. The timing of water will vary as the plant grows. I start with one minute of water every four hours and by the end of the season it will usually be five minutes every four hours. I judge the time by how long it takes for water to start coming out of the bottom of the container. I planted tomatoes on March 9 this year and my water time is now up to two minutes.

The next most important item is support. A large plant with a crop of growing tomatoes is very heavy and it is easy for them to fall over and break the stem. Initially I built 16' tall wooden towers with horizontal supports every 12", but have now switched to using PVC pipe. My plants will typically grow to over 15' in height and using PVC pipe allows me to add height as the plant grows.

If I knew how to post pictures on this forum I could show you what I talking about.

    Bookmark   April 22, 2012 at 3:13PM
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Ohiofem(6a Ohio)

I'd love to see photos of your set up. There's a description of how to do this that I'll link to below. The one thing I'll add is that you first need to get an account on a free photo site, like You can then find out the URL for your photo and use these instructions.

Here is a link that might be useful: How to post a photo

    Bookmark   April 22, 2012 at 4:24PM
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stev32k(Zone 8)

OK, I finally think I learned how to post photos so here goes.

The first is a shot taken a few years ago when I was using wooden towers for support. Notice the nylon shade sloth around the bottom of the containers. I had two other plants growing at the same time that did not have the containers shaded and could not tell any difference in either quantity or quality of the tomatoes.

The supports were made from 2X4's - 16' long with horizontal at about 12".

This year I used new pots after getting a split in one last year. Here is the sequence:

first I drill a pattern of holes in the bottom of a 35 gallon plastic garbage can:

Next I place some nylon shade cloth over the holes to allow water to drain out while keeping the dirt in:

Then I put in the support base. This is 3/4" PVC pipe with a "Tee" and 5" "wings" to keep the uprights from pulling out:

Finally I fill the can with potting soil - about 2.5 Cu. Ft. and add the plants. Later I put in the ring header I made from 1/2" PVC with a pattern of 1/16" holes to provide a uniform distribution of water around the container without digging holes when the water is coming out:

As the plant grow I add a PVC "tee", uprights, and a horizontal cross piece to tie off the vine. I only allow one main stem to develop so that the plant will get good air flow all around and the leaves will dry out. If the plant gets bushy and does not dry out pretty quickly each morning or after a rain fungus and mold will take over in a short time. This shot was taken Sunday. The plant is a "Parks Whopper" and is now 42" tall. I allow no more than 3 tomatoes per cluster and usually only one or two. I find doing that gives me fewer but larger tomatoes and I end up with about the same weight.

    Bookmark   April 24, 2012 at 9:06AM
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stev32k(Zone 8)

The only part of the PVC supports that are glued is the bottom with the "tee" and wings. The rest is just a friction fit. That lets me take everything apart at the end of the season and soak the pieces in bleach water to kill off any mold, fungus, or disease so they don't carry over to the next year.

I change out the potting soil and sterilize the containers every other year. If not I start getting disease early in the year.

I fertilize about every 7 - 14 days with Miracle Grow tomato plant food. I've learned to judge when to fertilize based on the distance between clusters. With proper fertilization the clusters will develop about 6" apart. Too much and the clusters will be 8" - 9" apart, under and they will be about 4" and very slow growing.

    Bookmark   April 24, 2012 at 9:30AM
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Ohiofem(6a Ohio)

Brilliant! Thanks for sharing that. The photos really help. What kind of potting mix do you use? Do you use any controlled release fertilizers or organic ammendments, or do you rely mostly on the Miracle-Gro?

    Bookmark   April 24, 2012 at 9:49AM
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stev32k(Zone 8)

I use Miracle Grow potting soil. I also add about 12 crushed tums pills to make sure there is plenty of calcium. Just put the tums on a freezer bag and beat them into powder with a hammer.

The only fertilizer I use the Miracle Grow. I tried using 13-13-13 one year, but I didn't get nearly the yield.

The tomato size is typically about 1.2 lb each. My all time record is 2.1 lb. Here is a typical (560 gm) Parks Whopper from last year:

    Bookmark   April 24, 2012 at 10:28AM
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Do you have a reason for using containers other than fighting with bermuda grass? (the grass from Hell, as I am certain that is how far down the roots go)
I am trying one, but my container isn't as amazing as yours, not by a long shot.

Another question for you: I am trying tomatoes because I had some grown in Camp Verde and they made the most delicious sauce. I tried again with store tomatoes. Not even close. Being a city girl, I had to do this in order to learn the difference. Do you think it's possible to even remotely replicate the great tomatoes with a custom soil mix and tender care?

You are certainly serious about your tomatoes! Thank you for the pictures.

    Bookmark   April 24, 2012 at 2:25PM
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stev32k(Zone 8)

I grow in containers for several reasons. The only spots in my yard that get enough sunlight to grow have underground sprinkler piping and electrical wires running everywhere and I don't want to cut any of them. I live very close to the Gulf of Mexico and the climate here is very favorable for all kinds of insects. That includes nematodes, mole crickets, cut worms, and other vermin that lives in the soil. They make a gardener's life miserable. Finally there is the grass and weeds that grow like crazy in a garden. Using containers I don't have to put up with any of that and there is much less work involved for much more production.

I think just about any well draining soil will work for container tomatoes. In fact I used to make my own, but it got to be too much work and I got lazy and just bought the potting soil.

I used about 1-1/2 cu ft of dirt I dug from an area in the yard, about 1 cu ft of peat moss, and 2 or 3 lbs of vermiculite, add a couple of hand fulls of 13-13-13 and mix the whole batch in a wheel barrow. It grew tomatoes just as well as the potting soil, but was a lot of work to mix and I ended up some big holes in the ground.

As I said in my first post - if you have good, consistent watering everything else is easy.

    Bookmark   April 24, 2012 at 3:01PM
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Stev32K, hope you're still out there and can help: We too get loads of insects which has been very discouraging to me as a beginner gardener. So I've been trying to think how to plant tomatoes in a garbage can and then make some kind of support that I could cover with window screening.

I went today and bought a cheap plastic 32-gallon garbage can, some flower/vegetable soil, plus a Better Boy and a Big Boy tomato plant. But I haven't figured out what to do next: can the 2 plants go in one garbage can? How would I both support the plants and protect from insects?

Another question: Why are the holes in the bottom of the can necessary? If I had a layer of sand and rocks in the bottom, wouldn't that water eventually evaporate in the heat? What if I put a layer of rocks and then inverted an 18" plastic pot in the bottom of the garbage can so that there's sort of an empty space for collecting water?

When you buy the PVC piping, does it come in those small pieces or do you have to cut it down? Not sure I can manage that on my own.

    Bookmark   June 18, 2013 at 5:35PM
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chilliwin(EU DK 7)

Stev32K, very nice work. Thank you for those awesome pictures and plants.


    Bookmark   June 19, 2013 at 3:28PM
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Bhamster, I'm not stev32k, but I thnk I can answer at least one of your questions, about the pipe. PVC comes in longer lengths, but it is easy to cut, either with a saw, or a special little tool you can buy. My local HD sells it in 10' lengths, and they will cut it in half to make it easier to transport.

    Bookmark   June 19, 2013 at 6:20PM
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mea2214(z5 Chicago)

This is quite amazing! I didn't think tomato plants could grow 16 feet high. How many months do you get in your growing season down there in zone 8? Also, do you employ guy wires to keep those 16 foot cages from blowing down in heavy wind?

    Bookmark   June 26, 2013 at 11:17PM
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edweather(Zone 5a/b Central NY)

Yes, very impressive! Almost expect to see a high diving board popping out of them :-) Yeah, tomato vines can grow extremely tall/long. I've seen some as long/tall as 30' in a greenhouse. I wonder what the world record is for longest tomato vine?

    Bookmark   June 27, 2013 at 1:00PM
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That PVC setup is awesome, I'm going to do that on my next one for sure.

    Bookmark   June 28, 2013 at 10:52AM
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Bhamster, I dont' know if you had one of your questions answered which is an important one. Do not add sand and stones at the bottom of the container, hopefully it's not too late. You need the drainage out of the container. Adding sand and stone takes away from the amount of potting soil which you need for good strong roots. not having holes to drain could invite all kinds of bacterial and fungal issues and if there are heavy rains, the plants will suffer. So, whatever you do, make sure you have drain holes....

    Bookmark   June 28, 2013 at 6:57PM
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If you don't put holes in the bottom, you'll have swamp-in-a-can instead of a tomato planter.

That said I don't know what the thinking is behind using such huge "planters". The only thing I can think is that you would have (virtually) a ton of planting medium weighing the whole thing down so it's not so likely to blow over in a high wind.

I get around that by making sure my planter is firmly attached to something super sturdy - say, the side of the house, or deck railing.

That's an awful lot of potting medium to go to waste though.

Have you ever tried sterilizing it via solarization? (Fancy term for laying it out and covering with plastic so it "cooks" out any pathogens, weed seeds, and/or harmful nematodes)

Depending on your potting medium you might need to amend the mix after resterilization. I have until recently always used equal parts peat moss, coarse vermiculite, and a good quality potting mix - not the cheap stuff that turns to black muck.

I used to use perlite but I really really hate perlite. And vermiculite has become difficult to find in coarse grade. So I'm working on developing an alternative mixture. "Al's Mix" is not much help as it seems to be composed primarily of unobtainium, LOL!

    Bookmark   June 29, 2013 at 5:09AM
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Ohiofem(6a Ohio)

Unobtainium: any fictional, extremely rare, costly, or impossible material, or (less commonly) device needed to fulfill a given design for a given application. -- Wikipedia

You're entitled to your own opinions but not your own facts. Pine bark, peat, perlite, granite grit and turface are not imaginary or expensive. And they don't require sterilizing.

    Bookmark   June 30, 2013 at 2:59PM
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funny use of a funny word...haha

    Bookmark   June 30, 2013 at 7:52PM
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drew51 SE MI Z5b/6a

"That said I don't know what the thinking is behind using such huge "planters"."

Tomatoes can have roots down to 4 feet. It is why experts say not to grow brambles where tomotes were grown. Tomatoes are prone to verticillium wilt, and you can't remove 4 feet of roots from the ground. They tend to break off. So near impossible to remove verticillium wilt because of remaining roots. No doubt those tomatoes go to the bottom of those containers, which are just about 4 feet high. Great idea!

This post was edited by Drew51 on Wed, Jul 3, 13 at 5:35

    Bookmark   July 3, 2013 at 5:19AM
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IMO the bigger the container the better for the tomatoes. They need the space to grow and if the container is too small it's non-stop watering. While the pine bark fines might be somewhat challenging to find in the right size, there are options out there. I am trying the 5 1 1 for the first time and had to make some adjustments, but so far I am having great results.

    Bookmark   July 3, 2013 at 5:29PM
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Re: Unobtainium

When I started using the word, it didn't HAVE a dictionary definition. It just means anything you can't get, for whatever reason. For instance, I was once taken to task for not using ships' mast locust in building my house (that I built myself, as in me with a hammer and nails). The problem with ship's mast locust is that at the time (something over 20 years ago) there was only on largish stand of the stuff left somewhere in the NE US, and it took about 40 years to grow a stand of your own. Hence, for all practical purposes, ship's mast locust was unobtainium at that time and in that place.

"Unobtainium" doesn't have to be fictional, or even rare - it just needs to be something you can't get without exorbitant expense or ridiculous expenditures of time/effort/money.

The unobtainium in Al's mix includes:

Expanded shale (as a replacement for turface)

The poultry grit is likely to be difficult to impossible to find if you don't live in or near a rural/farming area. Also difficult to find if you don't know where to look, which most people don't. That, at least, can be rectified by telling someone to go to the local feed store, if there is one.

Peat I can get. Perlite I can get but won't touch with a ten foot pole and as I recall it isn't even required in Al's mix anyway (there are alternatives). Pine bark fines may or may not be had with some effort - some places I've lived I've been able to find them, other places not.

But the turface and most of the stuff recommended to replace it is pretty regional in nature. Turns out expanded shale is a local item where I live NOW, but is unavailable where I will be moving in a week. And no, I can't load up on the stuff and take some with me - my son would have a stroke over moving gravel, LOL!

Some people manage to identify a local distributor but still can't get it because the distributor only sells it by the pallet. That makes it unobtainium, even if it is physically sitting right next door.

That's no reflection on the mix at all. If I didn't think the idea had merit, I wouldn't have looked into it (several times) enough to wax wistful about not being able to find all the ingredients.

You can get all huffy about it if you care to, but the FACT remains (as you state you want to rely on facts) that many MANY people have had great difficulty (as in "have failed totally") finding that particular ingredient (and sometimes one or two others) local to where THEY (not you) live.

    Bookmark   July 9, 2013 at 1:11AM
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As for giant size containers for tomatoes:

In 30 years of off-and-on container growing (I prefer square footing in dirt if I can) I've never resorted to such huge containers and my tomatoes have always yielded more than I could use. Possibly putting them in extra-large containers like that would have yielded even more, but when you already have an excess, a larger excess isn't necessary. I usually only grow one of each type of tomato I want when growing in containers. I grow only determinate types for the past 20 years; before that I most often planted indeterminate types and have found them not to be worth the trouble. Again - when you already get more than you can use, an excess of excess is really not required.

If you're growing indeterminate types then a larger container like that would be useful just from the point of view of not wanting your 8' tall vines to tip the container over. But it is not NECESSARY to growing plenty of good tomatoes.

as for 4' long tomato roots - possibly, if you count vertical growth. But I personally have not ever had a tomato put down any significant amount of roots past about 18" - that could be deeper in sandy soil, but not the clay loams I have typically gardened in.

And yes, I HAVE dug them up to check root depth.

I used to be a fan of deep planting of new tomato plants. I would dig, double dig, "work in organic matter". (NOTE: Don't do that. Let the worms do it for you. Encourage worms to work for you by planting cover crops and deep mulching when cropping).

Then when the bed was ready I would dig a hole deep enough to bury the entire plant except for the top couple of pairs of leaves, pinch off all leaves and branches on the way up, and bury the plant to its eyeballs.

The plants always seemed to grow just fine, but one day I came across an article that stated that planting tomatoes this way wasn't very useful because anything below about 10" to 12" just ended up never putting out any roots and sort of amputates itself off, and it's only the upper part of the stem that roots out. This doesn't really HARM the plant generally, but it doesn't exactly speed the development.

So the proposed method of planting instead is trench planting, fairly shallow comparatively.

Humph humph, sez I, generations of tomato-planting lore can't be so far wrong!

So the next year I planted half my tomatoes the "traditional" way (at least for my family) and half the doubtless silly and unhelpful new-fangled way.

And sure enough, the (relatively shallow) trench-planted tomatoes were sturdier, bloomed and fruited earlier, had fewer of the few problems I typically ever have with tomatoes, handled both torrential downpours and dry spells better, and eventually yielded more.

When I dug up the plants at the end of the year, sure enough, those traditional, deep-planted tomatoes had only rooted out of the upper 8" or so of the stem (the rest being the existing root ball). In many cases the perfectly preserved lower parts of the stem, including the original peat pots, were still to be found, like archaeological evidence in deeper layers.

When I say "fairly shallow" I mean that I never dig down more than 10" to 12" and plant the plant at an angle or on its side in the trench so that just the top 2 leaves are showing. I support the stem with dirt (backfill under the stem when it's at an angle) and bury the entire stem, but no part of that stem is any deeper than about 8" tops. (remember not to count the rootball, just the length of the stem, which is usually 6" to 8" by the time the ground where I lived was warm enough to put tomatoes out).

The truth is that the vast majority of root growth for a tomato in the ground (not in sandy soil but in moderately good clay loam) is in the top 12" of the soil. Tomatoes growing naturally (eg in the wild) sprawl, and root along their stems - eg ROOT SHALLOWLY.

You'd be hard pressed to find roots below 18" to 24", and not many at that depth. (Again, ignoring sandy soils, which I have never grown in).

Now container growing NOT EQUAL growing in the ground. In the super light container mix that one should be using in a container roots undoubtedly do penetrate deeper. But tomato plants do not need 4' of soil depth for proper root growth. They are a relatively shallowly rooted plant.

Now clovers, by comparison, are a different matter. A well established stand of some kinds of clover can have roots extending 5' or even more - at least one variety has had measured root length of 20'. Keep in mind though that that's total root length, a lot of which is horizontal - so 5' long roots do not necessarily extend 5' DEEP, and 20' roots CERTAINLY do not.

Clovers are, however, a very deeply rooted plant. That's why (when I was still dirt-gardening) I liked to use clover as a cover crop when preparing a new bed - first cover with cardboard to kill turf (weighted so it won't blow away of course) from fall into the next spring. Then dig out the dead turf and compost it, do just enough tilling to break up the top 8" or so of soil, broadcast seed buckwheat, mow, broadcast seed again, usually I could manage 3 buckwheat crops a season. The following year till again (now much easier due to the organic matter from the buckwheat stems and roots and incursions of earth worms) and sow a good clover. Let that go at least a year, two if I could manage it, mowing I think in the early spring (it depended on what clover I was using). One more visit with the tiller and I had a great garden bed. I would switch between 2 or at most four plots (depending on where I was at the time and how much space I had), using cover crops on the fallow bed(s).

Anyway. I don't dirt garden anymore, I am just not physically able and my son has zero interest. So it's pretty much containers all the way for me these days. Though when we're no longer in rental properties I would very much like to have a small square foot garden for things like icebox watermelon and other space-hungry things that just don't do well in containers. Garlic, some perennial herbs.

Anyway anyway.

I don't think there is anything WRONG with planting in such large containers, but at my age, at my size (I used to be ALMOST 5' 2" and have definitely reached that point in my life where shrinking begins, if it isn't already well advanced, LOL!) and in my physical condition - those containers are far to large for me to manage.

I get more tomatoes than I can handle from much smaller, easier to manage containers. I don't grow indeterminate varieties so I don't need the extra anchoring effect from such a large container. And I won't throw away potting mix after one use, won't use it unsterilized more than one season, and can't handle the weight and quantity just one of those trash cans holds.

It isn't NECESSARY to use such large containers. If you want to and can manage it, or if you are determined to grow an indeterminate variety in a container, then more power to you. It sure isn't likely to HURT anything (excluding possibly your back, LOL!). But it isn't NECESSARY.

People grow good tomatoes in 5 gallon buckets. Personally I think that's too small, I think the earthbox type containers are too small as well, but lots of people grow good tomatoes in pretty small containers.

I like a container that's at least 16" deep and at least that high and wide. That has been plenty big for the non-determinate tomatoes I most frequently grow.

Now if you're after beefsteaks - you can grow in that size container but you PROBABLY won't get optimal size fruit. Most of the better beefsteaks (IMHO) are indeterminate varieties (in fact probably ALL of them are) so that type of tomato would benefit from a larger container.

I don't think there's really anything wrong with giant sized containers, I just know they aren't necessary. Indeterminate or large-fruited tomatoes would benefit from a larger container though I can't say you would have to go THAT large - but they are certainly cheap, so why not, if you can physically handle a container that size and tomato vines 10' up in the air.

But don't get scared and think you HAVE to grow in containers that big. Any indeterminate variety, and many determinate varieties as well for that matter (if you don't mind regular pruning and redirecting of vines) can be grown in a MUCH smaller container.

Actually, taking one of those trash can containers and cutting the top off (so what's left is 16" to 18" deep) wouldn't be a bad idea either, since you can usually find those size cans for around $8 to $10. That would certainly be easier to handle. I may have to try that after we get moved. It'd probably make an excellent potato "bucket" too.

    Bookmark   July 9, 2013 at 2:23AM
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I misstated about the deep-planted tomatoes. The reference to the root ball applies to trench planted tomatoes planted in a normal year (when the plants go into the ground on time).

The year I "tested" trench planting vs vertical deep planting my tomato plants were taller than usual. Ummm, sure, that was planned so I would have clear evidence of how deeply the stem would root. I MEANT to do that.

At any rate the plants I used that year were taller than usual but still fairly stocky (there had been weather problems that made a late planting necessary). So they were a good 12" to 16" tall above the root ball. Which is way big for putting tomato plants out. Some later started plants were of about "normal" size and though the stem-rooting results weren't as obvious (because hardly any of them extended stem below about 10" of soil), the yield and plant growth factors were consistent with the taller tomatos - eg, trench planted were stockier, well-branched, sturdier, bloomed and fruited earlier, handled extremes of weather better, and yielded more fruit, and more unblemished fruit (less splitting,etc).

But I don't dirt garden anymore so ... I don't have to worry so much about frosts, mucky wet springs, or unseasonal hail. When you only have a couple of tomatoes in containers it's much easier to pot them up on time and protect them later, LOL!

    Bookmark   July 9, 2013 at 2:35AM
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drew51 SE MI Z5b/6a

"I've never resorted to such huge containers and my tomatoes have always yielded more than I could use."

You have a good point there.
My reference for 4 foot deep was what Don Shor said on his radio show, a master Gardner. I often listen to the podcasts. My tomatoes are not in deep pots, but next year I want try using deeper containers. I saw these on the net. they look thin, but I have no plans to really move them
27 gallons, out of stock at the moment!

It seems 2 feet is a good depth
Looking on the web here is another reference to the 4 ft depth of tomato roots

Here is a link that might be useful: plant root depths

    Bookmark   July 9, 2013 at 10:11PM
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I have several tomatoes growing in 10 inch diameter pipes....3 1/2' tall. They do well in these....with a good potting mix. In the past, I have found the roots had grown all the way to the bottom and "mushroomed" out. Making me think they wanted to chase water/nutrients even further!

    Bookmark   July 10, 2013 at 12:19PM
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