Perfect Plants Ltd (www.perfectplants.co.uk), based at Herstmonceux, offered free sunflower seeds to primary schools across the UK in a bid to get people gardening.
A spokesman for the company said it was delighted to receive more than 100 applications and these have now all been despatched.
The spokesman said: “Unfortunately supplies have now expired. Applications came in from all around the country, from London, Essex, Kent, Sussex, Surrey, Suffolk and Somerset to the Midlands, Wales, Scotland and even Shetland.
“The school with the fewest pupils was Foula Primary School in the Shetland Islands with one pupil.” The head teacher of the school said: “We have a poly-crub which is the Shetland name for a poly tunnel and last year we grew a few sunflowers in there. They went a bit crazy and were well over 7ft tall. We are hoping this year that we’ll be able to grow some in the poly-crub and also move some outside to see the comparison. We’ll also be using our sunflowers heads to feed our wild birds.”