thoughts on my raised bed idea?

[The Terps]

For 6 plants... I plan on building a raised bed instead of using fabric pots like I have done in the past (also done in the ground). I'm looking for thoughts on size of bed, type of soil and plant spacing.
So here is the plan a 4.5 Ft wide bed stretching 36 Ft at 2 Ft high giving each plant a 6 Ft spacing, as for soil its a toss up right now between 707, happy frog, and pro mix. My goal for my soil is to have approximately...
45% soil
25% coco(nutrifield)
30%perlite (#2)
I will be planting clones not seeds so the 2ft depth isn't necessary so I will fill the bottom 4-6 inches with gravel for drainage. I want to have a small plot with large plants. I will have both horizontal and vertical trellising cause my plants normally bush up to about 6- 10 Ft high and the same distance across (5-9) I hope to do a little better than that next season with this design though I think my plants will just barely touch buds at the end of flower. So thoughts and suggestions welcome. Its never to early to start planning for next season!

 

[tj Wise]

Big outdoor trees need to sink deep roots in such loose soil so they won't fall over after a hard resin with a little wind. Supports can help if they are really solid. Mine went sideways but I roped the horizontal netting to my fence and straightened them up.

 

[tj Wise]

Hard RAIN

 

[The Terps]

If you plant a seed plant roots will grow up to 2 1/2 Ft down but have never seen a clone put roots down that deep( unless in a narrow container). The trellis system I use is more than enough to take the wind, rain, hail, sleet, snow so if my plants do tip over I wouldn't blame it on the elements or soil it would fall on lack of trellising.

 

[Blaze]

You've got a good basic plan that should work well. Plans love raised beds, and the bigger the bed, the bigger the plant. My main critique would be that you will need to space your plants farther than 6' apart. With a set up like you are planning you should get some big ass plants, I would go 9' on the spacing, at a minimum. Crowding them together will do more harm than good. I usually figure the plant will end up about twice the diameter of the bed, so a 4.5' wide bed will easily grow a 9' wide plant.

Also IMO you might want to reconsider using coco and perlite, I do not like either in an outdoor mix. The coco takes forever to break down and tends to sink to the bottom of the bed and can create a nasty, slimy layer at the bottom. Perlite tends to float to the top over time and gets blown around in the wind. For outdoor all you really need for a base is some well drained soil, with good aeration, plenty of soluble organic matter (IE dairy cow compost) for good results. You don't need to spend a ton of money on fancy bagged soil mixes.

 

[The Terps]

I have had and heard so many complaints about all the soil yards in my area. Due to the shear number of yardage that gets ordered all year round they are super inconsistent with poor quality ingredients. The spacing is definitely my biggest concern! The guidelines in my area are pretty lame I probably could go 8-9 feet though I just don't want to waste a single sq ft.

 

[organicpanic]

If your worried about soil quality build your own. You are your own quality control.

 

[The Terps]

So I just pulled the tape measure around the yard for a bit and the best I'll be able to do is a 40ft bed and do a 7ft spacing. As far as soil I decided I will probably be going with happy frog I will be using it at a 4cu Ft to 1.75 cu Ft coco.