watering, stress 'n 6.5L pots

[x Big Dave x]

As im still playing things by ear a bit, im nearly 3 weeks in to veg but im wondering how harmful it is to deny plants water? I fed approx 72hrs ago (good soaking) and I know from before when I left them 4 days the soil was really dry and the plants had a bit of a droop on but after feeding they were fine.

Whats your expert opinons on letting them dry out like this frequently? is it too stressful for them? i've read the wet/dry cycle but im worried im taking it to the extreme.. basically I can't be bothered with the hours drive today.. I know today would be ideal but do you think im gonna harm them much by leaving them about another 16-18hrs?

Thanks ppl

 

[tester]

I always allow the pots to become completly dry usually i water then on day 3-4 i never let then droop though, they get a litre of water each pot, Watering tomorrow should be fine i just wouldnt make a habbit of it

 

[Kupunakane]

Yo Ho x Big Dave x,

Your thoughts are going in the right direction, and this is a good question.
I recommend a good moisture probe. I use containers that are 3 gallon containers, and with the probe I aim for the bottom center to get a moisture read. Drying out a bit is good as this allows you to actually stir up the top couple inches of soil with your finger, or a small garden tool.

This action of both drying your soil a bit along with the minor cultivation allows air to get into the soil. Packed soil that is very moist tends to set you up for problems like root rot, and critters that like to live in the top few inches too, along with assorted molds. On the flip side you can dry soil out so bad that it in a sense becomes water proof, ie. it won't soak up the water as normal...

So, as I said a bit of drying out without stressing your lady is GOOD...


smoke in peace
KK

 

[Locked]

I always try and let the soil get good and dry before watering...I go by the weight of the pot and look for the soil to peel back a bit from edge...I hve always heard it helps root growth by making the roots search out for water and grow...and of course it gets oxygen to the roots...right now my 4 ladies in my flowering tent are drinking like crazy so i don't go by number of days between watering because sometimes they need to be watered daily other times every 2 or 3 days...

 

[Alistair]

I'm with KK on the moisture meter. You can stick it in from the top, plus, you can stick the probe through the holes in the bottom of the pot in order to see how moist the soil is top to bottom.

 

[Tact]

As im still playing things by ear a bit, im nearly 3 weeks in to veg but im wondering how harmful it is to deny plants water? I fed approx 72hrs ago (good soaking) and I know from before when I left them 4 days the soil was really dry and the plants had a bit of a droop on but after feeding they were fine.

Whats your expert opinons on letting them dry out like this frequently? is it too stressful for them? i've read the wet/dry cycle but im worried im taking it to the extreme.. basically I can't be bothered with the hours drive today.. I know today would be ideal but do you think im gonna harm them much by leaving them about another 16-18hrs?

Thanks ppl

Yo, I am in the process of learning when to water my MJ myself. Getting a feel for the weight of a full pot relative to the weight of a half-way dry pot, then a ready-to-watered-dry pot, seems to take some experience to feel comfortable with. One thing though, there is no guide really available on a time basis because there are to many variables in play, the size of your pots, the drainage qualities of your soil, the temperature in the room, and the air movement in your room etc. When I added two oscillating fans to my grow room, I noticed the soil seemed to dry out twice as fast as when I only had one non-oscilating fan circulating air in the room (not on the plants), when the two oscilating fans were setup to rotate over the plants the evaporation rate of the moisture in the soil went up dramatically, I would water once a week before, if that, now I have to do it every 3-4 days. Like Kahuna said, a single-prong moisture meter (apparently better then two-prong?) can help you gauge the with of pots as you start to get a feel for them with a little bit of data as to what the moisture is being measured in the middle-bottom of the pot.

 

[x Big Dave x]

nice nice.. Thanks everyone, I kinda feel a bit more of an expert on it after reading your replies.

Thing is in the past I could tend to them every day and check when the pots were light enough, that side of measuring is fine but with these I am only tending to them as little as possible, long distance 'n all that. I like the sound of the moisture meter, if its cheap enough i'll pick one up. The last few waterings have been 3 days apart but the conditions have been changing over those 6-7 days. The drooping was because the temps for the first few weeks were around 30c (1 small fan, light too close) over the last week week 'n 1 watering (moved light up & added bigger osc fan) the temps are have been stable between 23-26c (73f/80f'ish) humidty is also way down between 20 and 30%. In those conditions they've really perked up growth looks healither and looks like my runt is gonna pull thru it's also helped that the air coming in is another 4 to 5c cooler. So basically so far so good, didn't bother going in the end, can't go now so i'll see what their saying tomorrow. Here's my runt that's doubled in size within 6 days with better conditions. I dunno why but I always got love for the lil strugglers, some make it.. some don't :cry:

2 weeks old then 3 weeks.



Thanks again for all the useful tips everyone, fingers crossed their not too peed off at me when I see 'em :angrywife:

 

[Tact]

Do you know what the water pH is you are using, and the runoff pH after you water your soil?

 

[Locked]

Hard to tell with those pics but it seems like there are ph issues...like Tact said what is your the ph of the water and nutrients that you are giving them and what are you using to check said ph?

 

[x Big Dave x]

run off ph is 5.6, this is the runt.. my others are doing much better

oh and I use a proper PH meter.

 

[Tater]

Read this, I won't argue with any of the posts in this thread because its not that the methods won't work its a matter of what is optimum.

hxxp://cc.bingj.com/cache.aspx?q=pearched+water+table+in+container+plants&d=4576820277477416&mkt=en-CA&setlang=en-CA&w=750949c1,49c8a46e

Thats a cached version of this pdf incase you don't want to download it but its kinda screwed up so i would reccomend reading this version instead.

hxxp://www.agf.gov.bc.ca/ornamentals/floriculture/aeration.pdf

Its not a big read but it does explain proper watering technique, what a perched water table is in container growing. It also explains total porosity, aeration porosity, and water-holding porosity and why they are important and how to measure them.

I see many people watering their plants with just enough water to moisten the soil and this is a BAD idea if you are growing with synthetics. It will lead to salt buildup and pH problems, lockouts and plant death. I actually just saved my friends 10 plants from certain death because he followed some bad advice from someone else on how to water plants and was watering them "just enough" to moisten the soil. By the time I got to them they were a day from being dead. I had to flush them and when I did I checked the runoff and the pH was at 3.8 and the ppm was at 3400.

No good.

Flush em, top dressed em with some organic love, and they are on a strict diet of water and rebounding quick.

The best (and only way to hand water if you ask me) is to water until you achieve a 10percent run off. This means if your container can hold 2L of you should water it once with a liter or so and let it sit for an hour then water again until you see about 200mL of water come out the bottom. This assures that all of the media is wet and stops dry/dead zones in the soil, plus it stops salt build up.

The reason for double watering is the same reason you wet a shammy before you dry your car with it. If the soil is dry it will repel water, its the water content of the soil that attracts and pulls moisture into it. This is because water is an odd molecule, it has a high adhesion AND a high cohesion rate. This means that it sticks to other things well and it sticks to itself well, so when the soil is wet instead of the water having to stick to the soil it can stick to both the soil and the water in the soil. Its high cohesion rate means that it is attracted to itself (basically).

So if you water dry the water will just run through and only wet portions of the soil creating dead zones in the soil and reducing the actual growing area inside the pot.