As part of "The Berserker's Trust" mission, one of the Berserkers you can do some missions for is Thorhild, a cultivator responsible for the seedlings. She's not the nicest person, but her missions are fairly easy and offer some solid XP and even an achievement. Here's how to complete the Thorhild's Cultivators mission and unlock the "Pass A38" Achievement!
Tools For The Cultivators
To start, you'll need to chat with Thorhild to see what she needs. She'll inform you that they need tools, and to talk with the Berserker smith to get them made. Head up to Lasse at the forge on the northeast side of the fort. Tell him he needs to make tools, and that Thorhild is demanding it and he'll begrudgingly agree to do the work - but in exchange for two things - time and iron. You'll have two options for what to smith - neither of which really matters in the grand scheme, so choose whichever you feel is best!
If you already have 25 iron (easy if you already did Scrappy's mission, Gas in The Mine) - you can give it to him now, and then head back to Thorhild to let her know. You can tell her you had expenses, but she won't like that and you'll only get 20 shards - so probably not even worth asking if you're going for low destruction.
Thorhild has another task for you though - some of the cultivators have run off, and she wants you to bring them back. There's only one place you'll find them - Chloe's Bar on the south side of the Fort. You're looking for Butch in the back - go ahead and talk to him and he'll say they want more shards before they'll come back to work.
You can talk to Thorhild about this - and you can either pay 2,000 shards on your own or head back to The Fort to convince Fenris to give Thorhild more shards for her people. Fenris doesn't have them though - and sends you to Tilas, who sends you to his assistant Raik.
How to get the Pass A38 Achievement & Complete Thorhild's Cultivators - Raik's Solution
You'll find Raik in Chloe's Tavern, and he'll pay you 150 shards then say it's a downpayment for his idea to solve the problem, but you'll have to come back. Head to the hut outside and to the left, and sleep until morning, then talk to Raik again. He'll ask you to follow him outside, where you're going to have to fight an Outlaw.
Once you beat up the Outlaw, find Raik again nearby - and tell him to leave and never come back. Talking to Tilas again, he'll let you know that Thorhild can have Raik's share - so give her the good news. Let Butch know and head back to Thorhild, where she'll ask for your advice and then let Fenris know you helped her. You'll also unlock the "Pass A38" Achievement for getting Raik to forgo his salary.