The things you learn growing tomatoes

[Fusion_power]

Every year I learn something new about growing tomatoes. This year I got a serious lesson about growing in cups. I've grown and sold plants in 4 inch cups for years. They were basic round 4 inch cups and a bit over 4 inches tall. This year I decided to switch to a square pot that is 5.5 inches tall by 3.5 inches across. My reasoning was simple that a larger container would give more room for roots and a better established tomato plant. I calculated that the square pot holds 25% more potting soil than the round cups. So I started some plants and monitored them carefully and guess what? They do indeed grow a bigger root system.

But!

The tops of the plants grow slower until the roots have fully expanded into the pot. The result is that a plant I expected to be 6 inches tall is only 4 inches tall after 4 weeks in one of the square pots. The difference is easy to see side by side. I need the plants to be a specific size in a certain number of weeks. The larger pots distinctly slow down top growth which affects the timing. I still like the square pots, but may have to buy them in 4 inches tall size.

DarJones

[Worth1]

The half pint jars worked great for me.
I have some pint jars and will see if I can come up with the same results.
I have read some plants do better root bound.

Worth

[livinonfaith]

Sad to hear that as I "traded up" from clear green dollar store cups to the pretty 4" square pots this year. I also thought I was doing the plants a favor.

Sorry this will affect your sales! For me it's just a matter of maybe waiting a week longer to plant. (because I like to bury them deep, which means they need a little height on them) Wonder if the extra root growth will make the plants healthier in the long run?

[swamper]

i would bet that the critical variable is soil oxygen or oxygen diffusion rate in your soil. There are probably macropores near the walls of the pots where those roots are getting more O2 than in the center of the pots especially just after watering. Decreasing the bulk density or compaction of the soil might also help.

[VC Scott]

I used both round cups and 4 inch square pots this year. What I found out is that it's a lot easier for kittens to knock over the cups.

[stonysoilseeds]

i tend to grow my plants on the cool side and try to focus on growing a heavy root system i usually have smaller tops when i set my seedlings out but when the weather settles and warms up i find my plants really catch up to others i know that buy much larger plants

[livinonfaith]

Originally Posted by VC Scott

I used both round cups and 4 inch square pots this year. What I found out is that it's a lot easier for kittens to knock over the cups.

Yep, the cups fall over way too easy! They also get awfully top heavy once the tomatoes reach a certain height. I usually get cheap containers with at least 4" walls that hold 6 to 12 of them. Keeps them safe from being knocked over and also makes it a lot easier to move around during the hardening off phase.

This year the dollar store had some decent ones, black plastic, kind of an open square pattern in the sides. (Like a laundry basket or a milk crate) That will be nice if they get caught in the rain. It's kind of a pain running out to empty all of the solid containers every time it rains. I think I'm going to make a little hole about 1" up the side of the solid containers. That way they will still hold a little water, but most of it can drain away.

[Irv Wiseguy]

I learned not to build a fence around the garden without a way to open it. Last year I put plastic chicken wire and an electric fence around my Earthboxes to keep the critters out. I didn't make any kind of gate because I could reach over the fence to get at the plants and Earthbox water tubes. It only partially worked because midway through the season something figured out how to get in and eat tomatoes. The biggest issue was one day I saw a hawk in there and it was unable to get out (probably went after a mouse). Its wingspan was too big to fly out of the small garden with all the Earthbox trellises in place. I shut the electric fence off and cut one side of the chicken wire fence down so it could escape. Irv

[Douglas14]

Interesting. I'm growing my plants in two different sized cups. 9 oz. and 16 oz. I was thinking of growing the plants that will go into my garden in the 16 oz. cups, and the backups and give-aways in the 9 oz. cups. I've started doing some of the transplanting into cups already. I'm about 1/4 done with this. I'm wondering if it even pays to transplant any more in the 16 oz. cups now. I thought having more root space would help the plants take off sooner when planting out in the garden. What do you folks think?

[brokenbar]

Originally Posted by livinonfaith

Yep, the cups fall over way too easy! They also get awfully top heavy once the tomatoes reach a certain height. I usually get cheap containers with at least 4" walls that hold 6 to 12 of them. Keeps them safe from being knocked over and also makes it a lot easier to move around during the hardening off phase.

This year the dollar store had some decent ones, black plastic, kind of an open square pattern in the sides. (Like a laundry basket or a milk crate) That will be nice if they get caught in the rain. It's kind of a pain running out to empty all of the solid containers every time it rains. I think I'm going to make a little hole about 1" up the side of the solid containers. That way they will still hold a little water, but most of it can drain away.

I bought a slew of those Rubber Maid-type "under the bed" thingies which are 8" tall, 18" wide and about 3 foot long. It cost me about $300.00 initially ( I bought 40 and each one holds 27 large cups.) I have used them now about 8 years. Best investment I ever made. I can power wash them with bleach and soapy water and they will never get a crack or leak in my lifetime. They store very nicely stacked at the end of the season.

[celerystalksmidnite]

Maybe you could pot up twice, in 9 oz first and then the 16 ounce? I have some plants in small styro cups that I intend to pot up several times before a late spring plantout. My target is to get as large of a plant/root system as I can without it being so large it falls apart. My hunch is the continued potting up will stimulate the root system, but it could turn out to be a case of diminishing returns. I love experimenting!

[celerystalksmidnite]

I bet those would make terrific planters with so much surface space! Less potting soil, and might be less apt to tip. I think I'll try it, thanks for the idea!