How to Get Berries and Grog's Belch
Berries and Grogs' Belch drop from clearing grass, or tending cattail, small fern, roots and mushrooms. So, if you need them, go on and click those in your neighbors. You will get these items and without spending energy.
How to Get Grubs
Grubs drops when you clear dead logs. If you don't have any, you can buy one from the market, by 250 coins. Be aware that if you don't have your limit of beasties, you can also have a wolf poping up when clearing this item, as all other forest items. If you are having problems to get them, try to clear dead logs in your kingdom and with beasties not maxed out.