compost blocker £5.09 Sarah Raven Sale

[irridium]

http://www.sarahraven.com/shop/make-your-own-compost-blocks.html is this worth investing at all? i've been keen to buy one for sometime now but have always been put off by the price (even now, i'm put off by the £4.95 del charge so i've got other things instead in the Gardening Kit section ie. the pea/bean frame and the bordeaux mixture).

can anyone care to comment on the use of these blockers, whether they do hold the soil together, and how do you go about "maintaining" it in terms of watering as the seedlings grow.

[irridium]

[goodlife]

I think they are supposed to use with compost rather than soil (soil would not hold together) and only for those 'quick-from-seed-to-planting' crops.
I know farmers plant manner crops in 'compost blocks' as we buy them by the tray full's to sell for members...and crops we sell in 'blocks' are things like beetroot, celery, bunching onion.
I suspect the item is on sale because it just doesn't sell here...people have got used to module trays that are cheaper and quicker to fill/handle. You still need good sturdy trays underneath the blocks...wobbly trays that bend will cause the blocks to break when there is movement. Those trays used commercially are very thick with only few drainage holes to allow some drainage so the blocks don't dry too quickly and the each block has couple mm gap between each.
When the blocks are made (for trade) they are made in huge quantities and straight on tables where they are to be grown on..developing roots will hold the blocks together and only moved to trays when they are taken to customers..and even then they are not handled individually but in bulk... the whole 'slab' of blocks just slide onto trays. When they are planted there is some root disturbance as some roots do venture into neighbouring blocks.

As for watering...fine water sprays...little and often to keep even moisture.   

I haven't used that kind of gadget myself, would love to try...BUT..I have feeling I would find it too fiddly to be any good for use any more than for small quantity of 'things'...and you would need to make the available holding container/tray full of them to ensure the blocks are kept evenly wet and supported. Looking at the photo..you probably fit 20 blocks for standard seed tray and you propably would need those 'solid' seed trays without grooves inside (flat surfaces inside the trays). Unless you already have something like that it might be 'job' to find them and they don't come cheap..those trays are £1-1.50 each
Oh..another thing about the trays that I've seen been used by trade..they are quite deep..deeper than standard seed trays. The tray edges cover the block edges all the way to the top if not even slightly higher.

I don't want to put you off, but to me module trays just sound so much easier option. The sale price is not expensive..but would I find regular use for it?...probably not.

[irridium]

thanks for your comments, GL. I do have doubts about it similarly to the holding together of the soil (meaning compost) and that it is used more commercially for veg growing. the main advantage of making your own blocks as opposed to using modular trays is the fact that there'll be less root disturbance, and secondly the ease of transplanting and space-spacing too. I can imagine the compost is compacted in tighter than you would for pot/tray cultivation so as to hold the seedling as it grows on. As I'm not very DIY-minded, I don't think I can make my own holding tray with deep sides and few drainage holes (don't own a drill!)

but here's someone else's piece about their own use of a compost blocker (wish i had theirs!


http://littlehouseontheurbanprairie.wordpress.com/2010/04/22/making-soil-blocks/

i'll buy one as it's on offer just to experiment. if it doesn't work for me, GL, you can borrow it