Flowering stage – watering and nutrients
I am about to begin my flowering 12/12 stage on my first ever grow, tomorrow. I know enough to stop using my veg nutrients and get some flowering nutes. I bought some 10-54-10 Bloom Builder from the advice of a nice lady at a local nursery (about my ‘tomatoes’). I didn’t want to ask too many questions … I had planned on beginning them on the flowering nutes immediately …? Is that a good idea? I think I have read to use just water during the first and last two weeks of flowering and the nutrients in between, but I can’t find that info again despite an extensive search. Can someone comment on that?
Also, I have read about PK 13/14. What is this exactly and how do I use it … or should I?
Edited Feb 11, 2012:
Carrying on from Campo’s comments on the Cloning Advice post regarding watering (I thought this might be a better place to discuss it… I copied/pasted your comment, hope that is OK)
Campo’ comments – “are you sure that you are not over watering max ? with experience you will know by the weight of the pot but for now here’s a useful tip which is pretty fool proof: 1) get two pots the same as what you are growing with and fill with the same dry medium you’re using for the plants 2) weigh one with some kitchen scales 3) take the other and water until the water starts to creep out of the pot 4) drain off until it it stops dripping, then weigh
the difference in weight will equal the amount of water retained by the medium for example, if your dry pot weighs 4 kilos and the watered pot 5 kilos this is a difference of 1 kilo which converts to 1 Liter of water now next time you water wait until there is 25% or preferably less of water retained by the medium so for this example I would water when the pot weighs 4.25 kilos or less
The weight of the plant is negligable at this stage (100g)
Overwatering is an issue when growing under LED grow lights … for this reason I switched from soil to coco – perlite. Next time I suggest you do the same, or DWC (deep water culture) or any other type of hydroponic system such as NFT.”
I am so confused! Let me explain. I am back and forth on whether I am over or under watering. Just want my girls to grow good and stromg! lol
I thought I might be overwatering, but have been very careful to make sure they get good and dry before I water. I haven’t gone as far as weighing the pots (no scale), but I do take note of the weight of a dry pot and after I water. I also stick my finger down the side … I’ll water when the top is completely dry (1-2 inches) and my finger tip all the way down feels mild dampness. I used to water them twice a week with about 600-700 ml of water, but I already noticed the droppy claws of the under growth. I thought it might be too many nutes, so I reduced the amount and even watered once with straight water. After about 3-4 days the top leaves which “always” stand up and look healthy, would begin to droop. Each time after I watered them they stood right back up looking healthy. I thought I was getting the hang of this, but the lower leaves still looked straggley and limpy. I only have small 2 gallon pots (partly to help control the plant size) and I am sure the roots are right to the bottom. I was noticing that the water never reached the bottom drain holes, so I decided to start using more water … 1 liter each per plant … I am thinking “maybe I am actually underwatering them” … ? I have been watering them 1 liter each every 3-4 days for about 2-2.5 weeks. Now just a tiny bit of water comes through the drain holes.
Now, just to confuse me more and make me consider underwatering again … I came home from work Thursday last week and they were all VERY droopy!! The plants had been watered on Tuesday (4 liters split between 5 plants cuz I only had 4 liters), As usual my biggest plant droops first but this time it looked just dreadful! (see below) The soil was dry, pots light so the only thing I could think of is underwatering, although that made no sense … I had watered them only 2 days ago and have never seem them as sad as this! I gave them all one liter and within 3-4 hours, they were all standing back up strong and healthy … except if you look under the canopy and the smaller under growth. I removed some of the big fan leaves around the bottom which seemed to just hang there covering the lower vegetation (they were droopy too, some laying flat on the soil) … 2-4 per plant … hoping maybe some more light exposure will help, but the top canopy is so thick (especially with all 5 plants close together) that I am not sure it will.
I did make one change this last week. Until now I was using demineralized water from a bottle (mineral salts < 10 ppm) treated by reverse osmosis. It was getting too expensive, so now I am using tap water that I leave sitting for 24 hours so the chlorine can evaporate. That is all I can think of … maybe my frequency of watering is OK but I should cut back the amount to perhaps 500 ml?