First attempt at crop, last stage problem..

Hi,

I am roughly 10 weeks in (yes, I should have kept a journal) and my 3 plants are coming on pretty well. Flowers are getting bigger daily, trics appearing all over the place and starting to smell sweet too. I am having a problem and need some advice. I was given the seeds and it turns out they are 3 different strains!! Hairs are starting to turn brown on one plant but hardly any on other 2. I noticed the leaves turning yellow and curling a few days ago and it looked like magesium lockout. I tried Espom salts for a few days (mixed with usual water & fert mix) but the problem seemed to get worse. I flushed all 3 last night and removed dead fan leaves. They look much better today but I have no idea when to harvest them. One plant has about 10% brown hairs, one has about 2% and the other has none. Im not sure what to do now as I dont want to over feed or underfeed my babies as they are real close to harvest and its my first go!! Please help.........

indica sativa? sative takes weeks longer usually. flush flush flush, and when trichs are cloudy/amber wait a couple more days and then snip

yellowing leaves on plants finishing up are common. even the upper leaves will yellow/brown near the very end if i understand right. ive removed several of my lower leaves and some others are starting to yellow. im at 10 weeks myself.some of my buds have had a slight purple/amber tint for maybe 5 days. no where near red. id like to see some pics of your plants just to compare to mine. good luck with the rest of the grow

Ery

I think its normal for the leaves at the very bottom to die but not ALL the fan leaves. The seeds I was given were ICE, Northern Lights and Skunk (apparently). all 3 plants look very different but are all about the same size. I flushed the hell out of them and the look quite a bit healthier now. I also removed all the yellow fan leaves as they were just dying. unfortunately I cant get my hands on a 30X magnifier in Ireland so I have to order one of the web. for now, i believe i can stop feeding when 30% of the hairs go brown, then only water for 7-10 days to flush ferts from plants. Is this a reliable way of judging if they are ready?? If I am unsure, is it safer to stop feeding them too soon rather then over fert them again? I'm using liquid ferts Biobloom, Biogrow and Topmax from www,biobizz.nl. I am following their instructions but this is the third time ive had to flush because of nuet burn. I don't have any pics either as my digital camera just died...... Thanks for your input guys, this growing can be a lonely process, its not like I can ask my green fingered neighbour for advice!!