Hi, I have bought cleared dug redug and raked 1 million times, my eeny tiny new garden. I followed teh instructions on teh grass seed packet, adn three weeks later my lawn is coming up nicely. However, it's a bit patchy. Esp where it's v shady. Can I chuck on more grass seed over the new lawn, or should I wait, or what can I do?? It needs to be ready for the summer so my toddlers can play somewhere..