Vermiculite or Perlite

Interesting info here:

http://en.wikipedia.org/wiki/Perlite

and here:

http://en.wikipedia.org/wiki/Vermiculite

 

Well first they can be horrendously expensive per bag in GC's ! I buy mine at Wilkos which is reasonable per 10 litre bag. This will last a season if you are an average seed sower. I use vermiculite as a light covering when I surface sow seeds. It is sterile , holds moisture and lets light through. So it make a nice environment for the seeds . Perlite looks like polystyrene balls , this I mix with the seed compost for my more delicate seeds to keep it light and airey . I also use it at 25% in my hanging baskets , its to expensive to use in all my planters.
Now does it give improved results - I don't really know without back to back tests !

 

I use vermiculite with all seed sowing either neat or mixed with multipurpose compost, holds the water but you dont get that soggy mess when just compost is used.

Perlite I use with Johninnes compost's to lighten the structure 25% , this year I am going to use this in my hanging baskets rather that multi purpose and see how they get on

Spruce

 

I bought a 100l bag of perlite from my local hydroponic place about 13 squid if I recall, it doesnt go off so will last a fair time.

 

My New begonia book they start all the tubers of in multipurpose , then after that John inns no 2 and thats for the show baskets as well , then Chempack no 2 every other watering at 1/4 strength of what it says on the box then July on wards Chempack no 4 same every other watering 1/4 , so having a go and we will wait and see , still going to put swell gell in the bottom of the basket in a cereal bowl as a reservoir.

Spruce

 

@fat controller
I should of said Perlite with the John innes

 

We *made* him buy that too, Mrs FC

 

Not really , I would buy both .

 

I bought mine, in years gone by, from a horticultural place in big bags (100L I guess). Last year I bought a bag from Hydroponics shop online as I was buying other things ... it was nothing like the same ... and that has caused me to realise that there are different grades. You could just get Perlite of Vermiculite as "insulation" from a Shed and I expect it would be cheaper, but I reckon it will be the wrong grade.

Hydroponics usage is pretty coarse. I think it is classed as P45 (which I think is 4-5mm). What I have found works for me is P25 (which I think is 2-5mm).

I used a lot more of the Hydroponics grade to get the "feel" in the compost, and I don't think it worked as well.

With the P256 grade I add Perlite 10% to Multi purpose 90% and find it significantly improves it. It improves drainage, not sure how important that is for most things, but the key thing I find is that it stops the compost compressing. If I pot something up in 100% Multipurpose and grow it on for several months the compost settles down (through watering) and it compacts. With Perlite that doesn't happen (a downside is that when potting on the rootball doesn't cling together as tightly / well, so can fall apart on repotting if the roots are not really well developed - its a minor hassle though, I think the plants grow on much better)

I don't bother for things that will be potted on quickly - e.g. Tomatoes - and I use more Perlite for things that need really good drainage. e.g. for cuttings I use 50:50

I use them differently. I use Perlite for drainage and openness of compost. Vermiculite holds more water, I think. I sometimes use 100% Perlite for cuttings (where stem rot is likely, such as with cane Bergonias like B. luxurians). When I worked on a propagation nursery they used 100% Perlite in raised benches for all their cuttings - struck directly into the Perlite, under mist, and then we steam sterilised the Perlite, in situ in the benches, before the next batch).

I use vermiculite as a moisture retaining layer over seedlings - "drizzling" it on in a thin covering. I also use it for sterile propagation - in zip-lock bags for things like Lily scales snapped off the bulbs and, with even higher levels of hygiene, for twin scaling bulbs (cutting the bulb up into tiny bits, each of which forms a bulb) like Snowdrops

I use very little Vermiculite, and find that a small bag from garden centre lasts me a season or more. Perlite I use a lot of and seek out good deals for purchase in 100L bags, my supplier is currently charging £13.50 for 100L.

http://www.lbsgardenwarehouse.co.uk...site&pf_id=R-PERL&name=perlite&sfile=1&jump=0

I buy it Trade (so that would be plus VAT), but they have it Retail at £17.81. Dunno whether you need Fine or Mediun, neither of those products codes is the one I buy!

http://www.lbsbuyersguide.co.uk/seed-perlite-100ltr.html

Just in case you can't see it without Trade login that page has this, which may be helpful, but the product picture shown is different, and the description seems to be talking about Vermiculite rather than Perlite - LBS's descriptions are often rubbish!!

Particle size:
Fine 0.15-2mm;
Seed 1-3mm;
Medium 1-5mm
Total water-holding capacity: Fine = 673ml water per litre Vermiculite.
Seed = 476ml/ltr.
Medium = 275ml/ltr.
Uses: Aid aeration, improve water holding capacity. Smaller particles hold more water whereas larger particle size increase aeration.

Different animals IMHO, but often described interchangeably