Having just read On Guerrilla Gardening: A Handbook for Gardening without Boundaries, I am feeling totally inspired and have started to organise an event for this magical day here in Sheffield.

There is a thread on the Guerrillagardening.org forums,  http://guerrillagardening.org/community/index.php?topic=3298.0
and a facebook group  http://www.facebook.com/event.php?eid=114409348583887
for the event. Sign up for either of those to keep up to date with the plans, or keep an eye open for news at  http://www.sheffieldsunflowers.org.uk

What you will need:

Sunflower seeds.
A bottle of water.
Something to make holes with (pencil, screwdriver, trowel, or in my case, a crutch!).

What to do:
Dig a small hole about 2cm deep, drop in a seed. Cover with soil. Water.

That's it! As many times as you like, in as many places as you feel will be cheered up by a glorious sunflower in a couple of months.

PLAN: If you want to meet up to plant the sunflowers, we will be meeting at 12 midday outside the Blue Moon cafe in Sheffield city centre, by the Cathedral (  http://www.tinyurl.com/368fz2c ). Please be prompt!

Alternatively, you can plant some seeds wherever you are in your locality.

There is also now a flickr group for this event:  http://www.flickr.com/groups/1367558@N25/