ebb and flow and grow tent ducting questions

9 years ago

So far I have built a DWC (lettuce raft) and an ebb and flow setup for tomatoes, my lettuce, black seeded simpson, and my gardener's delight cherry tomatoes have sprouted and are about an inch tall with tiny true leaves starting to form. I have a 400w MH lamp which I dimmed down to 50% and tried out for 2 days. Day one was ok, cuz I came home at lunch and misted the plants. Day 2 I did not mist at lunch, and I came home in the evening to several sad lettuce plants which had been baking and dried out too much even tho they were 22" from the lamp.

Since then I switched to a single 2' grow fluorescent which runs cool and I keep it about 3" away from plants. They are recovering nicely but I need to do something about the heat from that MH lamp.
My thermometer says 81-84 most of the time the MH is on, reaching near 90 tho without room fan on. However, from what I understand, 77 is the optimal temp for many veggies, is this right?

Another problem with the MH is it's super bright! The 11x10' room I have the setup in is lit up like daylight, and this room doubles as my study so it is kinda obnoxious. I understand that plants like tomatoes benefit from having 12 hrs of complete darkness to trigger flowering, and that may be a problem giving them darkness when I have to use the study to... study. So to resolve the light issue I have ordered the grow tent you see here: http://www.amazon.com/gp/product/B00H9O6UJ0/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1

I also traded in my light for a 600w MH with enclosed glass reflector and vent holes
for 6" ducting. I am planning to set up the light with an inline fan sucking air from inside the tent, thru the lamp and out to the study, which I will keep open to the rest of the apartment. With a fan on low, and no MH light, temps in the room will usually stabilize around 77-78, so I'm hoping I can at least cool down the grow tent even if the room stays a bit warmer than normal.

So I have a few questions.

1. My air flow is as follows: Surroundings>grow tent>left side of lamp>right side of lamp>inline fan>surroundings. Fan will be sucking, not blowing (snickers allowed). Will my ducting plan be sufficient to keep my plants around 77-80 F?

2. How soon can I put seedling under my MH dimmed to 300w, and how far should I hang the light above the canopy?

3. My next question is specific to the ebb and flow setup. How do you change the reservoir water when you have 4-6 large plants in a tray sitting on top of the reservoir container? I cannot just remove the tray and sit it down cuz it has plumbing running out the bottom. I could build a small stand for the tray out of pvc, I guess, but I am trying to avoid more expenses. I have already spent enough, lol! Plus then I will have to build one to raise the lettuce raft up too.

So this concludes my novel, thanks so much if you even read this far! I look forward to your helpful comments and opinions.

Kindest Regards
-A.H.

Sort by:Oldest

Comment (1)

grizzman
9 years ago
Hello Mirth. It sounds like you've got your hands full with hydroponics at the moment. Though I don't grow under lights I will share what I can / know. I'm sure there are others more experienced who'll help fill in the areas I can't.
As for changing the rez. Well that is the 1st rule that most of us learn the hard way. Always consider a means to change nutrients during the planning stage. Trust me, we've all been there :-) Probably the easiest fix for you currently is to add a drain into the bottom of the rez container and either elevate the whole system so it will drain or attach an external pump to pull the nutrient out. If you have a hydro store nearby go buy the adapter and then modify the fitting so PVC works. From there you can attach a valve for easy on and off. Personally I use drains on all my reservoirs for the plumbing issue. But in the future you may not want the EnF tray on the rez and be sure the connecting plumbing is flexible.
As for your venting plan, it will work BUT as you recirculate the air in the study it will increase in temperature as it picks up heat from the lamp so eventually the whole room will hover around 90 degrees. Unless the room has its own window AC unit, your house AC will probably not handle the heat correctly. Also, the increased humidity will make changing the temperature more difficult. You best bet with venting is to have your intake and output vents go somewhere where temperature is either unaffected or of little concern. (i.e. discharge into the attic)
Onto another topic; If you're growing Marijuana the 12 hour light cycle is necessary (don't forget the one hour on in the middle of that cycle I've been told). Tomatoes (or most of them) are not light cycle dependent to flower and fruit so you don't need that kind of dark cycle. If it were me, I would adjust the lighting cycle so the plants "night" cycle occurred during times I would likely be in there. But yeah, the freaky plant lighting can be kind of unnerving. I have grown indoors before just don't do it regularly.
As for lighting and plants, I believe the rule is: if you place your hand at the top of the plant and your hand gets hot from the light, the light is too low. If you can vent the light adequately so the tomatoes can near touching the glass you'l have a lot better success growing tomatoes and lettuce together. Otherwise the lamp height is dictated tomato and it get really far away from the lettuce plants.
Related Discussions
Ebb and flow - How long flood should last ?
Q
Comments (4)
I am letting my system run for five minutes with hydroton clay pebbles as the growing medium, because that's how long it takes to flood to the overfill level. However I have been reading something about flooding long enough such that 130% of your nutrient solution is circulated, in order to provide less nutrient salt buildup and better circulation. If that's the case I need to let it run a little bit longer... not sure yet. As far as water frequency, I have heard that it is best to time watering increments so that you water just as everything starts to air out again - thus taking advantage of all that oxygen around the roots in the mean time in between floods. However again, I am still figuring all this out myself. My plants seem to be dong well though so far.
...See More
Using a DWC reservoir simultaneously as an Ebb and Flow reservoir
Q
Comments (2)
Cool. It seemed rather straightforward, but I thought I'd ask to be sure. And thanks for the suggestion about the light color, but it is all for an indoor setup. I live in China and there isn't any outdoor space available since everyone lives in highrises for the most part, so I'm making do with some LED grow lights (you can get them for about a third of the price as they sell for in the U.S. because they are all made here and sold out the same factory with a different Chinese label) and a sunny southern facing floor to ceiling window in an unused bedroom.
...See More
Proper Ebb and Flow Cycle - Please Advise
Q
Comments (5)
Hey, thanks for the responses! @Pepper Man: Yeah, the HPS light just made sense to me, since I'm growing the flowering plants, but we'll see how that actually works for me during the initial plant growth stage. Also, I'd love to show you a picture of my setup, except I probably should have said "I have acquired a kit (that's still in the mail)." I'll likely post my pictures in a thread once I have everything set up. Also, I am just using rockwool cubes for the medium for now since they come with the kit, but I am seriously considering using pots full of the clay pellets for my next batch. This will, of course, have to change my strategy for the flood cycle, but it is good to know what to do for this initial experiment with the wool. Thanks a lot for sharing your nutrient plan; this makes a lot of sense to me and I will give this a shot. @greystoke: Thanks for posting, and you're probably right: my system/plants will let me know if my flood plan is or isn't working and I can make adjustments as I get more intune with my setup.
...See More
Fruit Tree Ebb and Flow
Q
Comments (11)
Normally, root mass is a function of plant size. In hydroponics, your plants won't really have a smaller root mass. You're just able to keep said mass all together since you're giving them food directly. Thus the roots don't have to go out in search of food (or water) The pot inside a pot is not really relevant to EnF systems as far as providing air to the roots. basically, during the drain, or flo, part of the cycle air is pulled down into the medium where the water has departed. That is how EnF aerates the medium. As far as container size, I doubt a 5 gallon bucket will be adequate for the life of the tree. a 5 gallon bucket full of medium might support one (maybe two) tomato plants when full sized and fruiting. So unless the trees are very small, it is just not big enough. The dwarf apple and orange trees I have seen are just not that small. Through the years, I've seen people come here looking to grow a variety of long term plants in hydroponics. I say this to you as I've said to them, without any intended disrespect or arrogance, but those types of plants are best suited to be stuck in the ground. hydroponics requires periodic regular attention and most people don't really want to maintain that kind of attention indefinitely. That is why it is best to grow single crop plants. That way when you're tired of tending to them and/or they've played out, you can simply kill off the plants and take a break. with a long term plant, like a tree, you don't really have that option. Now maybe your personality isn't like that. I would suggest you grow something smaller for a spell in a hydroponic system to see if you're really inclined to maintain an indefinite routine for a hydro system. Perhaps 6 to 8 peace lilies. That way when you get tired of tending to them you can simply pot them and give to friends.
...See More

ebb and flow and grow tent ducting questions

Comment (1)

grizzman

Related Discussions

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US