E-mail - Slugs in the Grow Tent!

I have a grow tent in my garage.  I found slugs in my grow tent, what do you recommend as I plan to eat my plants, so I don't want to use anything toxic.  I am growing in a soil mix I got from HTG

  The slugs are getting in from somewhere, you may have a small hole etc. in your garage.  They are most likely nocturnal, so you could go out at night with a flashlight and look for them.  Also, slugs leave a slime trail, which helps them move, but it also allows them to find their way back to the food, look for a slime trail coming out of your grow tent and you might be able to follow it to where they are getting in.

Slugs are easy to control, you just have to sprinkle sluggo all around the grow tent.  This is made of iron phosphate, so you can put it in the soil around your plants, and even around the outside of your garage.  Just make sure you put a lot of it down, you want to make sure the slugs crawl over it.  The sluggo will be absorbed by the slugs, and it interferes with an enzyme in their digestive system and they no longer can eat, and they die.
I have written a post about slugs and snails with pictures of damage, if click here if you want to see it.
Good growing,
Dr. E.R. Myers

Click here to order Sluggo!

Here is a picture of a leopard slug, it does not have its antennae extended.


E-mail LED and Vegetative Growth

I've just purchased this LED from HTG Supply.  It's a 90w with 3 color wavelengths (red 630-660), (blue 450-460) and (orange 610-615).  I'm using it with 4 plants (clones) for 12 hours a day with the light 1.5 meters above the plants.  After 2 weeks using this light, I'm seeing minor amounts of flower initiation.  I've increased the light to 16 hours a day now but have a lingering question....is there a problem with using this 3 color LED light during the plant growth phase?  It seems to be a great light for my application.  Thanks- 

 You are growing a short day plant. (Read my post on Plantflowering) If you want to make sure the plants do not flower anymore, you could leave the light on 24/7 for a couple days, or take the length of the day (time light is on) to 20 hours.  Read my post on speeding up flowering
If you got the LED from HTGSupply.com, then you are fine for all growth phases.  Plants need red and blue and some secondary colors to grow.  Blue light is associated with vegetative growth, and red with flowering, and your LED has both.  I have found that the LED's keep the plants growing short and stocky during vegetative growth phase just like when I used fluorescents and plants flower as good as with an HPS
So, you are fine.  Let me know how things turn out with your LED.
Good Growing,
Dr. E.R. Myers 



The Right Length of Day To Make Your Plant Flower

 To understand plant flowering, you need to understand a term "photoperiodism," which is the amount of light and darkness a plant is exposed to. The amount of uninterrupted darkness is what determines the formation of flowers on most types of plants.  Uninterrupted is bold because this is very important.  When growing indoors you want to make sure your grow area is light proof or you may not get any or very poor flowering.  Some growers  think that the length of daylight a plant is exposed to determines when a plant flowers.  However, scientific experiments proved otherwise. It is the length of darkness that a plant experiences that plays the most crucial role.

A plant that requires a long period of darkness, is termed a "short day" (long night) plant. Short-day plants form flowers only when day length is less than about 12 hours. Many spring and fall flowering plants are short day plants, including some strawberries and Christmas cactus. If these are exposed to more than 12 hours of light per day, they won’t flower.

Other plants require only a short night to flower. These are termed "long day" plants. These bloom only when they receive more than 12 hours of light. Many of our summer blooming flowers and garden vegetables are long day plants, such as, lettuce, spinach and potatoes. These all bloom when the days are long.  And some plants form flowers regardless of day length. Botanists call these "day neutral" plants. Tomatoes, corn, cucumbers and some strawberries are day-neutral.
You can do an internet search for the plant you grow to see if it is a short day, long day or day neutral plant.
Good Growing,
Dr. E.R. Myers


E-mail - Grow Tent with LED in Garage

Thanks Doc for all of the great information, my grow tent is located in the garage and so the humidity levels can get rather high. I also had opened the lower screened vent flap in hopes that I could pull in some fresh air but now thinking about it, all I am doing is letting more humidity in. I did run my fan all day and was able to get the humidity down to 71% (10pt drop) and the indoor temp was at 85 degrees. I'll keep monitoring the levels and see what happens. my readings this morning were 84/64 which is a whole lot better. I think the readings yesterday were about 88/72 +/-

Another question that I had was about the light intensities of the Led Lamp. I have a 120watt Tri-Band Led that has a dimmer on it. I had run the lamp at full intensity at first but was getting what I was considering "High" temps near 90 degrees so I dialed back the intensity of the lamp to finally where I was yesterday, 81 degrees and 81% humidity. I then turned up the intensity to the lamp and turned on the fan and was able to get much better readings.(85/71) So here's my plan, close the screened vent at floor, run high intensity, run fan and watch my watering. What are your thoughts?
You should keep the LED 2-3 feet above your plants and I'd recommend keeping it at the maximum intensity if you can, this will maximize growth and yields.  I only use a dimmer for a carbon filter, if you are growing in a smaller room, you can use the dimmer to have the fan blow less and the filter last longer.
Are you using a thermometer with a min. max setting?  I ask because I was growing some plants up in an attic once.  I had the lights on during the night since I figured it got hot during the day.  Every evening I'd go up and check on the plants, and the temperature was in the 80's or low 90's, high but ok.  The plants were not growing well, they were stretching between nodes and had big odd shaped leaves.  I put a thermometer up there and realized on sunny days, the attic temperature in the afternoon with the lights off was over 130F.  That is too high, and I had to move the plants to a new location. I was only checking a regular thermometer in the evening after it cooled off.

Now, if you are concerned about humidity and temperatures you can get a thermometer/barometer with a sensor to get your fan to turn on when the temperature goes over 85, and the humidity goes over 60, I would highly recommend that.  If you do not have problems though, you do not really need to do anything.

Good Growing,
Dr. E.R. Myers


E-mail - LED, Grow tents, humidity and temperature

Hi Doc,
I read your blog about led's and grow tents temps. I have a 39x39x79 AgroMax tent with  a 120watt Tri-BandLED. When I first set it up I was getting temps in the mid to upper 80's with very high humidity. I was afraid it would be too much for my plants so I turned on the 6" inline fan filter combo and it reduced it some but I didn't want to run it all of the time. I also have a smaller fan which is on a timer with the led and the inline fan. After that I turned down the intensity to the led and have turned off the inline fan and am now getting temps in the low 80's with about the same humidity. I also have the timer set for 18/6. What do you think? Should I go to full intensity at 24/7 or should I stay where I'm at? I don't want to damage the plants with high temps and humidity. This is my first indoor growing attempt any and all help would greatly be appreciated.

Hello again,
Thanks for the E-mail, glad to hear you are reading old posts. 
Most plants do well in the 80's.  Lower is better than high 80's but not by much.  You need to worry about heat stressing your plants when you get in the 90's and you will have problems with most plants above 100F.  Make sure you take the reading at the top of the plants, LED's do not give off as much heat as an HID, but that will still be your maximum temperatures. The humidity is most likely not going to be a problem for your plants however; you may have problems with mold if you have high humidity.  Ventilation can help with this.  A lot of people have problems with fungus when their plants start to flower or fruit develops so if you can get it down to 50% now, you will have fewer problems later.

You did not mention what medium you use, but watering the plants less can also lower humidity.  Plants need to take water from the soil and push it into the air (called transpiration) but if the medium is also evaporating water you will have higher humidity.  If you are using soil, make sure the top dries out before you water again.  You may need to experiment to find the best medium moisture for your plants with the lowest humidity.

I hope this helps,
Good growing,
Dr. E.R. Myers