Hi I 'own' the Planet Guinea site. I only sell products that are guinea approved (by my own crew).
The Cereal grasses are so easy to grow if given light, warmth and moisture. There is an option to soak/sprout them first but personally I don't do that, you will receive instructions on 'how to' though in case you want to.
I regularly get 'edible' grass within 14-15 days (It does depend on conditions but it doesn't take much to get them right
For indoor growing I recommend one of or a mix of the Cereal Grasses (Organic and no dust/compost, 100g of seed).
Wheatgrass is my favourite but the guineas really don't mind.
Wheatgrass is the sweetest with Barley being least sweet if you need to take that into consideration, Protein is 18-20%.
I can supply trays and labels if you wish PM me and I'll work out a price.
The hay and herbs on the site also goes towards the upkeep of the Rescue Guineas here. They recommend the Alpine as opposed to Herbal though they do eventually eat most of the herbs. We are hoping to test more herbs out on them soon.
Apologies for the 'Hard sell' but now you know
When the site is fully up and running I'll let everyone know
Also look on the guinea pig section on Ebay I sometimes have some on there.