That support goes an astonishingly long way, with ISSA's 20ac site fulfilling an enormous number of roles.
It is a gene bank, an arboretum, a seed producer, a tourist attraction, an educational resource, a research station, a proving ground for novel varieties and a living reference library for gardeners and farmers.
"We get a lot of calls and email queries from people looking for advice and we try to help where we can," said Jo Newton, seed collection co-ordinator at ISSA.
There are 13 gardens, orchards, woodlands and nurseries packed into just 20ac. Currently, ISSA preserves 500 varieties of herb, vegetable and grain, and about 80 potato varieties.
Each year, the association supplies thousands of packets of seed that are either heirloom Irish varieties or unique foreign varieties that perform well in Ireland.
"Part of our work is to find varieties that are useful to Ireland, so if we get a plant that doesn't perform well in Irish conditions, then we drop it," Ms Newton said.
"This is a living, growing gene bank. It is a research resource."
But even more than the gene bank, the orchards and the heirloom variety vegetables, the attitude at ISSA is perhaps its most impressive achievement.
Earlier this year, ISSA joined with Michael Miklas, of the Biodynamic Association, to save processing equipment that was going to be dumped from the Mallow sugar beet factory.
"The factory had a very important seed-production and breeding programme," said Matteo Pettiti, ISSA's orchard co-ordinator. "We hope to put the rescued seed-sorting equipment to good use soon."
In yet another project, again with Mr Miklas, ISSA is working to preserve Irish heirloom oat, barley, rye and wheat varieties, like Stormont Arrow or Scotch potato (both oats), or Old Irish and Glasnevin barley.
In a blog entry, Mr Miklas made the point that floods on the continent damage the seed harvest, with enormous potential implications for Irish agriculture, which produces no seed. Moreover, native grain varieties are more suited for organic production.
In every area of Irish agriculture, ISSA is working to conserve agricultural traditions, all in the name of biodiversity.
"It's ironic," Ms Newton said. "You tend to think biodiversity means forests and wilderness, but 70pc of our landscape is human managed, so biodiversity begins on the farm, under your feet. The more people you have growing food and saving seed, the more food security you will have."
ISSA has been working tirelessly to that end since it was set up by Anita Hayes in her back garden 19 years ago.
This extremely rapid development is a testament to the hard work of ISSA staff and volunteers, and a reflection of the vital importance of its work.