The latest wallet now has a "Growing" feature which will increase the total amount of coins available. 250,000,000 is the total coins to be mined.
I have yet to "grow" any hempcoin but what it says is that after 45 days growing starts and is completed 45 days after that.
I am not sure if this feature works with paper wallets but if it does you could make a paper wallet at http://hempcoin-paper-wallet.github.io/hempcoin-paper-wallet/ and use it like a savings bond. Store it for 2 years and your coins will go through 8 growing cycles. (100 hempcoins * 1.05 growing cycle * 1.05 * 1.05 * 1.05 * 1.05 * 1.05 * 1.05 * 1.05 = 147.74554438 after 2 years)
Could someone confirm that "growing" will work with paper wallets? You do not have to have your qt wallet open all the time to grow do you? I am wondering about this because I locked my wallet and it says "Info: Minting suspended due to locked wallet".