First. Head towards the Grand Exchange and purchase Two or Three Guam seeds. They are pretty cheap. 500 - 800gp. Well, when you have that bought, head towards the farm, just South of Falador. It is in between Falador and Port Sarim. Make sure your on a members world too. Go to Sarah, and right click on her, then click trade. Purchase the seed dibbler, the rake, and the spade. Go to the stile located near the dairy cow, and climb over it. You'll see two allotments, a flower patch, and a herb patch. Go to the herb patch near the compost bin. Right click your rake, click use, and then click on your herb patch. Once that is done, right click on your weeds, and then click the compost bin. They will all go in. Go back to the herb patch and right click use on your Guam seeds. Click on the herb patch, and you will begin to use the seed dibbler by putting the seeds. Luckily, it doesn't need any watering or plant cures, so head on to Port Sarim. You'll soon see a logo on the min-map with fire. Go into that building and trade Betty. Buy 10-20 Eye of Newts (rough estimate). After that is done, head back to Sarah who is in the house. Buy 10-20 potions of cure plant (I know, it's a lot of money.) Empty all of the vials, then head to the sink, also located in that same house. Use one vial on the sink and it will fill the rest. These are used to make the attack potion. After a bit of time, your guam's will be finished growing. Pick the plant, and then clean off all of the leaves. Put the leaves in the vial, and then apply the eye of newt(s). Soon you'll have a good herblore level, and some nice money after selling the potions in the grand exchange.