In the Varrock Achievement Diary Hard section, under the Poison Ivy (farming) requirement and the Addy med helm (smithing) requirement, it mentions that you cannot use potions or assistance to complete these tasks. However I have verified (by doing it myself) that you can actually use a Dwarven stout(m) to boost your smithing level by two levels, so you can complete the smithing requirement at level 71 instead of 73, and you can also use the Summoning familiar Stranger Plant (requires Summoning level 64) to boost your Farming skill level by three levels, so you can complete the 'pick poison ivy' task at Farming level 67 instead of 70. I am currently level 71 Smithing and level 67 Farming and have completed both of these task by doing this and now have the Varrock 3 armor.