Sure why not...may shock them a bit but they will come back and be better off in the long run.

What kind of tomato are they? Some varieites would be ok in a 3 gallon, but not most.

wild_forage,
I have one of each of the follwoing:
big beef
mortgage lifter
sun sugar (cherry kind)
roma (determinate)
Thanks for replying.

beginner_2008

Roma and sunsugar will do fine--- just not produce much without constant water ( EVERY day if its hot ) and often feeding : )
Geno

Thank you to you all. Your feedback make me feel a lot better now: no longer in despair about my poor tomatos.

beginner_2008

I'd definately aim for larger containers with the big beef and mortgage lifter. The roma is probably the only thing I'd put in a 3 gallon because it's determinate, but some people would still use a 5 gallon for that.

A neighbor is moving, so she gives me a 10 gallon and three 5 gal containers. I'm going to transplant all four tomatos to big pots, and will keep my finger crossed for bigger and healthy tomatos in August!
beginner_2008

3 gal containers will work on most tomatoes if you have good soil. Dirt volume is not the main issue. Tomatoes need sun, water and nutrients from the soil. They don't need dirt( maybe space but not always such as hot and dry areas which discourage curly leaf carriers and shad fruit). I grew 5 foot high Roma's in 6 inch deep square foot SFG plots . These 5 plants gave me two crops of about 25 tomatoes per day each lasting 3-4 weeks.
I used compost peat and vermiculite. 3 gallons of soil is probably at least double the soil I used. It would be better you concentrate on good soil than container size.
The Romas should be fine. I also grew an heirloom beefsteak right next to these and it was an 8 foot vine that produced several tomatoes per week.
If you want to water less take an old cotton T-shirt and put it along the side of the container in the dirt. Put the other side in a gallon of water and the wicking will moisten the soil.
See this link.

http://forums.gardenweb.com/forums/load/sqfoot/msg0310241914233.html

solanaceae - You made the same point in an earlier thread here and as was explained then by several of us, comparing growing in a container to growing in a Sq. foot bed just isn't comparable. They are very different situations.

Your plant in the Sq. foot bed had far more soil available to it that just the 6". It's roots are not contained within that 12"x12"x6" plot as they would be in a container. They had all the rest of the bed as well as all the soil below the bed to roam in. They can't do that in a small container.

Thus the amount of soil available to the plant in a container IS relevant and is important. And for an indeterminate variety of tomato a 3 gallon pot just isn't enough. 5 gallons is the minimum recommendation made by most all experienced container gardeners.

Dave

digdirt,

I had weed fabric at the bottom of the box. When I pulled the plants at the end of the season they did not penetrate the weed fabric. So the 2 rows of tomatoes did not have the extra space you speculated they had.

Here is what they say on the FAQ.

"The key word is "improved". When I realized you still had 6" of usually poor growing soil (and most people around the country were telling me they had the worst growing soil you could imagine) I started experimenting with starting out with just perfect growing soil.

My experiments showed with good homemade compost, the original 3 ingredients I recommended in the book worked just fine. In fact, all plants grew in just 6" of the perfect soil mix.

So it turns out that all plants will grow better in 6" of MelÂs Mix than 12" of ? MelÂs Mix and ? native soil in most parts of the country. Later I confirmed that this was true all over the world and I suspect it will be true even on the moon. There are of course some exceptions as some places have very good natural soil.

The 6" does need watering more often but 8", 10", or 12" deep beds also cost a lot more. If youÂre still a little skeptical I would suggest you do a trial with 6" and another with 8" deep with 10 or 12" for the vertical vine type plants. You can do all of the above with 6" size lumber by digging down as suggested in the book (see page 117) to add to the 6" above the ground. Let me know how you make out."

These are the space recommendations and it is 1 vine type tomato per square foot that will be expected to grow in 6 inches of soil.

http://faq.gardenweb.com/faq/lists/sqfoot/2003112433023631.html

A 3 gallon container has more space than an SFG square foot. The indeterminate in 5 gal is certainly safer and I do prefer 5 gal because of watering. However I would rather have 3 pruned space efficient plants than 2 sprawling plants. Here with the newer popular upside down method.

Here is the quote

"Studies have shown that 5 gallons is the ideal container size to maximize the space/production ratio of tomato plants."

Romas and other determinate varieties certainly leave the guess work out of it but is probably overkill.
http://www.growing-tomato.com/Growing_Tomatoes_Upside_Down.html

I know for example Maine Organic gardeners grow them 14" apart in a green house for there best production per square foot. That what they say, not me. It is certainly similar to SFG recommendations. This is not per plant but per square foot.

I also know what mine did in confined space. Its mostly about available water and nutrients. Soil that holds water and nutrients is going to outperform alternatives in larger spaces. If you are not using good potting soil then I suppose 5 gal is better.

Ok, so no lower soil access. It would still have some moisture and nutrient access, but no soil.

What about lateral soil access? Did you discover there was no lateral root migration either? A 5' tall, tap root plant actually remained all contained within that 12"x12"x6" space? That would be a miracle.

Dave

A 3-gallon container doesn't have more space than an SFG square, if you mean a 6-inch deep one. One foot by one foot by 6 inches is, of course, .5 cubic feet.
Three gallons equals .4011 cubic feet. Five gallons is .6685 cubic feet.
So the square foot bed has 25% more soil space than the 3-gallon pot. It's also not exposed to heat on the sides as a pot is. And, water can wick up from the ground below.

cloudy_christine,

Looks like you are correct.

1 cubic foot = 7.48051948 US gallons. So one is working with less soil.
Still very possible to grow many varieties of tomatoes for people with limited space. Since Mel does not even top dress I would guess that doing this could mitigate the situation.

As to heat exposure it depends on the container and climate. Plastic will heat up but use less water. I am in zone 5 so heat is not so much an issue.
Also as I said you can take a water bottle and a cotton cloth and wick water into the container or use self watering containers. I use the wicking method on several containers and I certainly water those much less. I made this a priority where some containers will not be exposed to rain.

The lateral root migration has little bearing on the issue since these plants were 1 foot apart and only found the root of a competing plant. Some probably did have more space but shade on the north side of the box was more on and issue. The tomatoes did so well they shaded out the cucumber vines to the north I started later, being blocked by 5 foot plus bushing Romas.

The plant on one of the corners should have been most affected but was not. I did tend to have earlier tomatoes in that bed than my peers because I had them the 1st week of July in Chicago which is unusual. They got to 5 foot plants they probably detected some water stress and fruited which was something that I wanted with Romas anyway because I am looking for pulp rather than too much water. In the past I would not water the Romas so much anyway. Given their blight resistance and my goals I tried packing them in. I had three tomatoes blossom end rot out of hundreds of fruit so they were not terribly stressed.

Since people grow different varieties from Florida to Alaska for different purposes I am not going to assume someone can make general comments about someone growing a Heat Wave and Rainbow vs a Sub-Arctic 25 and a Sasha's Altai. Toms are very diverse flexible plants these days. I don't think my Red Robbin needs much more than a salad bowl to grow in.

I have gone through 3 phases of gardening. When I grew up I had plenty of space and grew row gardens. Later I lived near my parents in an apartments and did week end gardening from time to time. Now I have more limited usable space and I have done a lot of reading on the issue as well as some personal experience with compact gardening. My conclusions are that large varieties may be grown in limited space with 5 gal containers probably being the best trade off between space, expense, soil management and flexibility. Perfect soil and drip irrigation will do very well IMHO.

All I can say is what I have witnessed from others using compact methods and what I experienced. I consider last years Roma attempt very successful with an early, bumper crop.