Seeds

Seeds are by far the hardest currency to earn in the game. They are also of high value, being the only currency you can buy premium mills or seed mills with. The easiest way is to pay money to buy some in the game. Short of that, the only other options are the following: If you are an iOS user, logging in daily and completing quests will get you 23 seeds per week. This is 100 seeds a month, and 1196 a year.
 * 1) Weekly Mission (Complete all steps to get 1-9 seeds)
 * 2) Weekly Streak (Wait until the end of the streak before accepting the gift)
 * 3) Watch Ads or Complete Offers (Android users only)
 * 4) Adding Friends (Possibly Android users only)

If you are a non-iOS user, logging in daily and completing quests and getting maximum of 2 seeds from ads/offers will get you 37 seeds per week. This is 160 seeds a month, and 1924 seeds a year. (Some offers are more than 1 seed; however after approximately 3 months most of those offers will be completed and only 1 seed videos will be left)

BUYING seeds: NOTE: Truck package is no longer available! It was removed during the same update that added frugality & substantial packages.
 * 1) LVL up sales
 * 2) * 50% off Large Box (240 seeds, $9.99), available for 24 hours after leveling. Only available on levels 1-20, then on multiples of five after that: 25, 30, etc
 * 3) * 30% off Large Box (240 seeds, $13.99), available for 24 hours after leveling. Available on non-multiples of five after lvl 20: 21, 22, 23, 24, 26, etc
 * 4) Monthly sales
 * 5) * +15% more seeds on Large Box ($19.99, 276 seeds instead of 240), Cart ($49.99, 805 seeds instead of 700).
 * 6) * Available certain days of the month, usually announced on forums and on facebook.
 * 7) Starter package
 * 8) * Only available for purchase once, but has been "reset" before so that it could be purchased again by those who had already bought it, potential to be reset again in future. $9.99 for 220 seeds.
 * 9) Regular packages
 * 10) * Always available, packages have been added or changed in the past.
 * 11) * Bundle (10 seeds, $.99), Basket (53 seeds, $4.99), Small box (110 seeds, $9.99), Large box (240 seeds, $19.99), Junior Pack (320 seeds, $24.99), Frugality Package (NEW 440 seeds, $29.99), Cart (700 seeds, $49.99). Substantial package (NEW 1100 seeds, $69.99)