For a couple of months, no. 3 weeks to 4 weeks max depending on the type of plant before the plant becomes rootbound.. 3.5' pots are quickly out-grown by many things.

But then there are very few plants that you would want to leave in a pot that small for long. So what are you growing specifically? What sort of large healthy plants to set out? That will determine the size you need.

Keep in mind that the plants you see at the nursery were not grown in the containers you buy them in. They have been transplanted into gradually larger containers at least 2-3 times before sales.

Dave

Dave, with the greenhouse, I'm planning on getting a decent jump on the growing season, and this year I'm growing:
tomatoes
beans
radishes
carrots
celery
corn
peppers
cucumbers
broccoli
Brussels sprouts
peas
spinach
lettuce
various herbs
A lot of these things I will direct seed, but the ones that I can start early, I will. So I'm thinking maybe purchasing 200 of the 3 1/2" pots, and maybe 100 of the 6" pots, that should give me enough for the larger plants to "grow into". Does that sound like a good plan do you think? I got into food preservation last year, and completely fell in love with it. So I'm hoping for a much better harvest this year.

So peppers and tomatoes then. Everything else on your list is best direct seeded anyway.

Peppers are slow growing so those might work for them depending on how far in advance you start them. If you use the standard 8-10 weeks prior to transplanting to the garden and transplant them into the 3.5s when they are 2 weeks old they should hold until garden time.

But 4" pots would be better and the square pots always work better than the round ones as they fit in the standard trays. The round ones waste tray and shelf space..

Tomatoes need deep pots to go into. SVD 355 @5" deep work much better for them (or you can just use 16 oz. plastic drink cups like many do).

You can also find better prices than the site you linked. Several gh supply vendors sell regularly on ebay this time of year with big discounts on bulk orders and often free shipping. Novosel Enterprises.com also has better prices. Check them out.

Dave

For the tomatoes and peppers definitely need a square 1 gallon container when they get bigger like the size of mine that is just transplanted today into a 1 gallon pots. to keep them for the next week or two until i get my greenhouse that i ordered here. if you would like you can check out my youtube channel i am just starting out myself but have a lot of hort background from school. I don't have very many videos up yet but i will be adding how to's and such very soon over the course of a few months.

Here is a link that might be useful: TheItalian Garden