Salem

I looked at Sevenless guide, and he said if I want to raise one element for my seeds, for example, say i want mercury, I would have to pick the seeds with highest mercury and replant them, and does this imply when I harvest I will get seeds wtih higher mercury?
Then the question is, how do I decide which elements I want the seeds to specify into? If only the highest elements will be raised, then will I have to buy new 25/25/25/25 seeds and gamble my luck on finding seeds with elements towards the one I want after planting these?
I really dont quite understand this aspect.

I think it is random so you might have to do alot of planting/replanting to get the desired results. Possibly influence influences this a bit? Im not sure crop rotation influences this maybe just affects plenty. Anyone have the details?

id love to know this as well. i was wondering if the fertilizer effected it. like you plant npc cereal then use say 40+ lead dross on it would that then impart some of that lead on to the crop there by changing it to say 30 points of lead. or is it really just random...

i have random element crops now days. like one field will be 30/30 merc/lead the same crop seeds planted at the same time on another field will be 30 salt but both received the same ferts :/ its all really confusing..

You cannot influence the purity of your seeds in any way. One exception to this is Pumpkins, where if you have humus of the purity you desire, numerous plantings of first stage pumpkins (Baby Bears), in gardening pots, will slowly raise their value in that element.

You just have to hope you get lucky, when selecting seeds for planting look at the elemental values not the overall purity. I recommend planting seeds with the highest overall purity, and one lot with the highest value for the individual element you are trying to raise. Most people just go with the highest overall purity, although you need to examine the individual elemental values when you start from 0% because it will take a few plantings to bring out some elements to over 1% (overall purity).

What you eventually want is 100% in your desired element and 0% in all the others. Keep this in mind when starting out. if you have seeds with say, 29 Salt, 20 Mercury, 20 Sulphur and 31 Lead, then it's likely that some of your next harvest from planting these seeds will have more Salt in them than Lead.