Aged pine bark is exactly what you want. peat does not expand, don't worry about that. You must be thinking of coir which come in compressed bricks. I suppose if peat comes that way it may expand, it does not come compressed here. The 5-1-1 is by volume. I myself think it is way too dry and use a 3-1-1 mix. I mostly grow vegetables. If using for house plants 5-1-1 makes more sense. As often overwatering happens easily indoors.

This mix is a general mix and should be tweaked depending on plant grown. It's a good mix for beginner's and a good base mix for advanced gardeners. If you're in the UK I would suggest listening to Gardener's Question Time on the BBC radio. I like the show a lot and listen to podcasts. In the UK many use compost in containers too, which I myself think is an excellent idea. It adds bacteria, and prevents root rot. I add it to most of my container mixes and have had excellent results. Add 1 part to the mix.

As far as the nitrate, well how you fertilize is up to you. Follow label directions. I'm not sure of the purpose of the nitrate with pine? I guess because it has no nutrients to speak of, and in the UK almost all potting soils have nutrients so they are concerned about it. We add nutrients each time we water or use time released fertilizer or a little of both.

Thanks again Al. As I've been reading more posts, I've become ever more confused - I think that's what delayed me planting up last Autumn. Should I actually be going for the gritty mix? The last thing I want to be doing is having to re-pot 7 (95x30x60cm/ 3ftx1ftx2ft) balcony containers every couple of years. I'm going to be using an automated watering system so I'm less worried about the mix drying up. And adding fertiliser regularly is hardly onerous! So, I'm guessing that for me, the decider between 5:1:1 and Gritty is what I'm planning to plant...lavender, rosemary, jasmine, rose, peony, spring bulbs, one container will be ericaceous (camelia, acer) , hydrangea, verbona, geranium etc etc - mainly perennials and/or evergreens, plenty of fragrants, with annuals for colour splash. Probably a typical beginner-lady's container garden! What, oh what, to do re the mix?! I really do need to get the growing medium ordered this week...

Great discussion.

I don't have much to add....but, yes, for the lavender, rosemary, jasmine, rose, I'd say Gritty Mix would be a better option (although my sister grows rosemary in 5-1-1 with great success). The Hydrangea I definitely see as being better paired with the 5-1-1.

Josh

Thanks Josh! It is so kind of you to respond, I hope you know how much we all appreciate it!

I've just clicked that weight is going to be an issue with the Gritty mix. I saw Al's post substituting in perlite for granite grit, tho he cautions about it holding more water. Is it really ok to do that? Should I go 50:50 between perlite and granite grit (if I can find the latter)? HOw would it effect the ratio with the Turface?

In the UK I just can't find Turface - I'm being directed towards Tesco (supermarket) Kitty Litter as being the nearest option which I find kinda laughable! Its made out of Diatomaceous Earth, though has added perfume, apparently. Anyone in UK have a more convincing sounding option for US Turface?!

And is it right that - if I can get it - using Dyna-gro FP 9:3:6 means not having to add any gypsum or Epsom salts?

Are there ANY Brits who have successfully found the ingredients who could point me in the right direction of any retailers? (I'll re-post this with the 1:1:1 heading too)

Hey, you're welcome!

Easy question first: with Foliage Pro, no need for gypsum or Epsom salts.

Do NOT use any product with perfume or scent added. But hard-fired DE is very suitable for container mixes. Just be advised that products may vary from region to region, and bag to bag.

Gritty will be quite heavy, and yes you can sub the Perlite for granite. More Perlite, less Turface (or DE). I think Al would be the one to field this question regarding tinkering with the ratios.

Josh

Thanks Josh. Going big on kitty litter tomorrow! One last question before I jump in - one of my containers will be ericaceous. What do I add to the Gritty mix as fertiliser for this one? Am planning on getting the Dyna Pro FP 9:3:6 for the other containers...

I'm not really sure. For acid-loving plants, such as blueberries, I'd be using a variation of the 5-1-1, without adding the Dolomitic Lime.

Josh