Flushing vs. Overwatering in Soil

I realize this topic is probably worn out, but every thread I have read that discusses it seems to end up in different opinions. Some people say you are supposed to flush every watering when using soil, others say you shouldn't. Some say to let the soil become almost completely dry before watering, others say to water every day. Some say to feed every watering, others say to feed every other watering. In your experience, what has worked best for your plants?
 
Here's my experience:
 
I am on my second grow. The first one (three sativa plants) turned out very good, but I had some issues with watering and nutrients (deficiencies, overfeeding, lack of nutrient uptake, etc.). When I start out in veg, the plants look awesome until flowering. Then I start seeing yellow spots, brown spots, and shriveling on the larger fan leaves after switching from 18 hours light to 12 hours. The plants were grown in 9-gallon pots with reservoirs in the bottom that let the soil breathe and drain. I used MG soil with perlite added and Flairform nutrients.
 
On my second grow I currently have three White Russian indica plants and one Eldorado sativa. I started out with two more of the sativas, but they were about a foot shorter than the other 4½-foot plants and died when I put them into flowering. I am beginning to think that I overwatered them in my attempts to flush the salt out of the soil, and the smaller plants weren't able to transpire as much water as the larger plants were. I don't think it is a nutrient issue, because I changed nutes and the same symptoms are there. If it was a nute issue, the larger plants would have also died.
 
One of my questions (and possibly an answer in itself) is this - why did the two shorter plants die when switched to 12 hours of light? Is it because there wasn't enough hours of radiating light to allow the plant to transpire the level of water that a 5-gallon flushing leaves it with? I didn't change anything at all in my procedures except for switching the lighting to 12/12, and within a few days the two shorter plants just shriveled up and died. I'm guessing that if I would have watered until I saw just a little runoff (instead of flushing until I got 3-4 gallons of runoff), they would still be alive.
 
I have been under the assumption that I need to flush the salt out of the soil before feeding to avoid nutrient uptake/lockout problems, so I have been doing that for the past few waterings by running about five gallons of water through each pot. However, the more I flush, the more the plants look unhealthy with signs of overwatering even though I have waited four days between waterings. The same thing happens even if I add a few ounces of H2o2 to the water. The room stays between 75F and 78F all day and night with about 50% humidity and fans.
 
The four plants I am currently growing are about three weeks away from harvest and the buds are thriving. But up to one-third of the leaves on plants are shriveling and turning brown on the edges - which looks like overwatering based on the images I have researched online. The other two-thirds of the plants looks healthy except for the sativa that has yellow fan leaves at the top of the plant only (which makes me suspect nutrient uptake issues).
 
I read a thread today that said you should only water a plant in soil with barely enough to get a little runoff each time, and that you should wait to water again until your finger comes back clean when you stick it a few inches into the topsoil. Then you should flush the soil 10 days before harvest. Based on my experiences so far, I am guessing that is the best way to keep from overwatering and doing damage to your plants.
 
Maybe some of you can enlighten me and others on your experiences? What were some of the mistakes you made with watering in soil, and how have you learned how to avoid them?

 

 
Bummer, but glad to hear I'm not the only one. All of the conflicting info is enough to make your head spin!
 
   

 

 
No offense taken at all. But you can't blame me for reading things wrong when every Tom, Dick, and Harry says that their routine is the best and they all conflict. How does a newbie know which one to believe? Because of this, I had to learn the hard way.
 
You mentioned the use of H2o2. Some swear by it, some say never use it. That is a perfect example of the conflicting information that I read on this forum and others like it. In a thread like this one, it's rare that two people ever agree on feeding, watering, and lighting (the three most hotly debated topics around here). So I walk away thinking one way, and then someone "enlightens" me with their post that conflicts with the most recent post, leaving me not sure what to believe and experimenting based on what the "experts" on here instructed me to do.
 
I'm sure that I am no different than a lot of the newbies who come here trying to learn the art of growing killer herb. When Bill says "do it this way and flush, flush, flush" and then Bob says, "No, that is false - do it this way, or your plants will be dead", where do you go with that?
 

 

 
 

 
The problem is that I have done too much re-reading a lot of stuff and it all conflicts with each other, resulting in the brain-on-fire phenomenon that Forty Winks referred to. Way too much conflicting information, with a lot of it being downright inaccurate and worthless - resulting in the dead plant phenomenon.

 

 
It's not "my idea of flushing" - it's what a lot of people post on here. The only things I know are what I have read here, and most of them conflict with each other. What part of that do you not understand? Reading this forum is like reading the Bible - many of the verses conflict with others that you just read. In one thread about overwatering and overfeeding you can find dozens of conflicting theories.
 
The real problem is that we have hundreds of "teachers" on here who all wrote their own textbooks, and they all conflict with each other. Is it my fault that I didn't know which one to believe? You can bet that I won't make the same mistakes again after learning the hard way as a result of following incorrect advice on flushing that I read on this forum.
 
You say I should buy my weed instead of learning the right way to grow it? How ridiculous of a statement is that? If you can't figure out how to post something helpful without bashing someone, maybe you should buy some better weed to chill those hostilities? It's not rocket science - lol. 
 

 

Here's a quote from this forum about H2o2 - what do you guys think of this?
 
Over Watering

Both soil and hydroponic plants often fall prey to the same syndrome. Hydroponic crops often fail due to "root rot" and soil crops succumb to "over-watering." The actual cause is a shortage of Oxygen at the root zone, allowing a Pythium infection to take hold.

In a soil system, the soil consists of particles, a film of water on the particles and air spaces between the particles. When too much water is put into the soil, the air spaces fill with liquid. The roots will quickly use up the dissolved oxygen within these pore spaces. If the root system has not absorbed the water within these pore spaces, air will not be able to enter and Oxygen within that space will become depleted. In a low oxygen environment, roots will begin dying within twenty-four hours.

As the roots die, the plant's ability to uptake water and nutrients will drastically decrease, and the plant will show symptoms of nutrient deficiencies (pale leaves, and slow growth). Plants will start to wilt (appearing water deficient) – at this point many growers will mistakenly water their plants!

In a Hydroponic system, oxygen deprivation is often caused by high temperatures and inadequate nutrient circulation and/or aeration. High reservoir temperatures interfere with Oxygen's ability to dissolve into water. Temperatures above 70F (20C) will eventually cause problems, 62F-65F (16C-18C) is recommended.

Oxygen deprivation symptoms in hydroponics are similar to that of soil - but at least you are able to check the roots. Healthy roots should be mostly white with maybe a slight yellowish tan tinge. If they are a brownish color with dead tips or they easily pull away there is at least the beginning of a serious problem. An organic, ‘dirt like' rotting smell means there is already a very good chance it is too late. As roots die and rot, they remove Oxygen out of the water; as Oxygen levels are depleted even further. more will roots die - a viscous circle!. Reduced Oxygen levels and high temperatures encourage anaerobic bacteria and fungi, which attack the plant further mercilessly.

How does Hydrogen Peroxide prevent root rot & over-watering?

Plants watered with H2O2 will experience extra oxygen in the root zone when the peroxide breaks down. This helps stop the Oxygen from being depleted in the water filled air spaces until air can get back into them. High Oxygen levels at the roots will encourage rapid healthy root growth. In a Hydroponic systems, H2O2 will disperse through out the system and raise Oxygen levels as it breaks down. Strong white healthy roots with lots of fuzzy new growth will be visible. This fuzzy growth has massive surface area allowing for rapid absorption of the huge amounts of water and nutrients needed for rapid top growth. A healthy plant starts with a healthy root system.
 
H2O2 comes in several different strengths: 3%, 5%, 8% and 35%, also sold as food grade Hydrogen Peroxide. The most economical is 35% which we recommend be diluted to three percent before using. When working with food grade H2O2, it is very important that you clean up any spills or splashes immediately, it will damage almost oxidize everything very quickly. Skin will be temporarily bleached pure white if not washed cleaned. Gloves are strongly recommended when working with any strong chemical.
 
Food grade H2O2 can be diluted to three percent by mixing it one part to eleven parts water (preferably distilled). The storage container should be opaque to prevent light from getting in and it must be able to hold some pressure. If three-liter pop bottles are available in your area they are ideal for mixing and storing H2O2. There are twelve quarter liters (250ml) in three liters, if you put in one quarter liter H2O2 and eleven quarter liters (250ml) water in the bottle it will full of three percent H2O2 and the bottle can hold the pressure that the H2O2 will generate.

Three percent Hydrogen Peroxide may be added at up to 3 ml's per liter (2 1\\2 tsp. per gallon), but it is recommended that you start at a lower concentration and increase to full strength over a few weeks.

For hydroponic applications, use every reservoir change and replace twenty-five percent (one quarter) every day. Example: In a 100L (25gal) reservoir you would add three hundred ml's (3%) H2O2 when changing the nutrient. You would then add seventy-five ml's more every day.

 

 
Wrong and wrong. You obviously don't have a clue. Calling me stupid in your first paragraph only makes you look like an idiot.