Like most iOS farming games, we can use the airplane mode trick to cheat the Smurfs.
1. Turn on airplane mode;
2. Plant some crops, build a house, etc.;
3. Change system clock;
4. Return to game and harvest your crops;
5. Repeat 2-4;
6. Change the clock back to the current time;
7. Turn off airplane mode, and sync your game.
Note that Papa Smurf will scold you for possible cheating: “I’m disappointed that you’ve been overworking the Smurfs by changing the clock. Careful or Smurfs will leave the village” at step 6 because the game detects the clock has been reversed (actually I think this is the only way the game is able to detect cheating). However, the game won't punish you for this by actually reduce your smurfs number, because this may screw some players for'ever I guess. Anyway, so far it's safe to do so despite Papa Smurf's warning. For your own safety, backup the game at another iOS device so that you always have a legit copy (this may not reduce all the risks but so far it's the best way to get an insurance).
What should I plant? Basically, plant whatever you like to enjoy the game. However, if you use the clock cheat which is described above, surely there IS a best strategy.
cheat cycle = 24 hours (minimum taps for the clock cheat)
below level 27 (currently only snails and caterpillars are available for me)
*Do NOT use future time during the cheat! Otherwise the friendly animals will not be available for you.
So, in one cheat cycle, you can use exchange 10 gold for 1 exp. Of course, in X cycles, 10 gold gives you X exp.
And for the crops:
So potato: 150+3*X exp; Golden Potato: 30+15*X exp. So how about comparing the golden one with the normal one?
30 + 15 * x - 150 - 3 * x = 12 * x - 120 (12X-120)
Cheat more than 10 days, then you should choose the golden one. Thus:
If you don't mind adjust AM / PM during every cheat cycle, you can use corn instead of potato:
Note that now the cycle is 12 hours and we earn 1 exp during 2 cycles. So calculate this:
154 / 20 * x + 44 - 12 / 20 * x - 155 = 142 / 20 * x - 111 (7.1X - 111)
Cheat more than 16 cycles (8 days) then you should choose golden corn.
15X+30 vs 7.7X + 44
Since X should be larger than 10, potato will always be better. And you'll save a lot of taps during the clock cheating! Just set the start cheat time much earlier.