Good Morning everyone!
My name is Drew and I am new to gardening. So new in fact I haven't actually started but planning to next year. I live in Hartline Washington and plan on purchasing a 20' x 20' greenhouse in which I want to place raised beds. It will have 3.5' sidewalls with roll up sides. The raised beds will be 12" high. I have been playing with the layout trying to maximize the amount of actual growing space. What do you recommend I do for spacing or layout? I am initially coming off each wall 6" as I don't want the sides to interfere with anything I plant. Not sure what is comfortable spacing between the beds will be. Any ideas or information would be greatly appreciated.

Sincerely,
Drew

As a starting concept, a bed width of 3-4 feet is common, as it allows reach into the middle from both sides without stepping in the bed.

Add to the above, research how the sun is at different times of the year and how tall the plants are likely to get. 3.5' would not be sufficient for tall crops, and they would shade out the lower growers, so would need to be the farthest from the sun. It will be a learning experience for you, but worth it. I would think two beds with paths down the center and on each side for access, but that would depend on which direction you faced the green house when you build it, and the seasonal vegetables you want to grow. Follow the sun and make yourself a diagram that you can turn as the season changes. then start researching what you want to grow in each season. Most winter crops are relatively low growers, but summer crops Can be tall. Also keep in mind that flowering crops need pollination. Lots of thing to learn, but you have long winters to read and plan.

If beds line the walls, think about how to work and reach all the way from the path.

I pictured a sloped roof. Beds along the walls may need to be shorter things, maybe using the taller center for some way to trellis, or at least stake or cage something taller. I saw a video with tomato plants hanging from hooks that run along a wire.
tomato roller hooks
https://www.amazon.com/dp/B00ZRMI48Q/

Thank you for your inputs. I am hoping I can attach a couple pictures to show what I am thinking.





This first picture is the greenhouse I am getting. The second shows the layout. Please do not pay attention to the actual plant placement. The quantities are about right but I haven't placed them correctly yet. The plants shown are ones I would like to grow. I used an app called growveg. Does anyone have any experience with this?

Hard to tell if that will work due to planting /harvesting time, but I think you are being a bit to optimistic about the spacing.

Ditto, some items shown as one square foot will take more like 4-9 square feet each- but maybe that's part of what you meant about arranging..
3 foot paths are nice, glad you weren't skimping there.

A layout similar to these would allow you to grow short plants right up to the side walls, but still have access to everything from the inside.




Something like this would allow shorter plants along the walls and larger plants in the middle that could be worked from either side.


Let us know how you proceed. Nice to have you with us in the Greenhouse Forum!

Carol, as always very erudite postings! I need not try to improve on same, except to mention to the original poster, that it will be really difficult to contain Zucchinis to a four-foot bed? Good luck!

Thank you all for the inputs given! This design was based on doing most of the planting as a square foot garden. Certain things like the tomatoes will be trellised. This is what the application showed is possible for spacing. has anyone used this application from the website growveg?

Looking better. But I still think the space allowed for single broccoli, cauliflower, summer squash, sweet potatoes, and potatoes are too small. Tomatoes in one square foot, maybe but you must prune and tie them up.
Now, maybe some of those can sprawl out of the sides of the house if you keep the sides rolled up in summer. Start the season early by using the greenhouse early warmth, but let things like sweet potatoes grow out.
Lettuce possibly fit into various corners early in the season, they go to seed and are gone before some other things (squash, watermelon..) spread out. Spinach would work that way too.