Questions about first grow


I just received my Grobo unit and have started my first grow. I am using the Generic Sativa recipe per suggestion from Grobo support with Maui Wowie feminized seeds. I recall seeing a very long grow time when picking the recipe, I think 120 days approximately. I was expecting a grow time of more like 90 days. The app doesn’t show any prediction of total grow time or harvest.

Will the real grow time actually be 120 days, or is this just an estimate? How does the machine know when it is time to harvest?

Thanks in advance for help for this Grobo newbie.


Hi scsouthern,

This is a common misunderstanding that new growers experience. You are looking for new seeds and you see an awesome strain that says, flowering in 90 days or simply states 90 days on the package. It’s a total marketing gimmick and not the full truth. The 90 day number does not take into account germination or vegetative grow time. This easily adds a month or more to your ‘flower timeline’. Sativa’s can take anywhere from 8-11 weeks to flower and ripen, on top of the 30-45 days of germination + vegetative growth.

The good news is that it is entirely up to you to make the call on when to harvest your plant. When given a 2 week window, you have the power. I’ve developed a ton of notifications we are rolling out soon to help educate you on what to look for and expect as you get closer to harvest time.



Thank you for the information. It would be great to have more info about harvesting!


Thanks scsouthern,

For more harvest info, check out the notifications beginning at week 11. Week 11 Notification



Hi Stephen, for my first grow I selected an Auto indica blueberry… day 7 and looking good …I have a couple of questions concerning Auto’s I believe you mentioned that you couldn’t control the height? Did you mean via changing the light schedule as you could with sativa or indica? What about topping? I read elsewhere that autos were smaller with smaller yields in general… On your grows of autos did you have a satisfactory yield? The faster time to harvest would ,I’m sure affect the yield but it’s nice to have an option if your planning on going on a vacation and want a faster harvest…I’ve also read elsewhere where the potency of the auto’s is now similiar to indica, sativa or hybrids… Isn’t the auto “indica” blueberry actually a hybrid with some sativa? Thanks Kirk


Hi Kirk,

Great questions, let me see…

You got it, autos change to flowering on their own time, not as a result of changing the photo period. Most autos are not topped as you don’t have enough veg time to get them to recover. Not saying it can’t be done, just not common practice.

Yields are smaller than photoperiod strains, most often it’s one big cola with a smattering of smaller nugs. The age old trade off of time vs yield!

The potency has certainly improved as breeders get more stable strains happening. I’d say that most are on par with photoperiod strains.

The auto blueberry recipe is " a beautiful inbred cross of a Lowryder #2 male from the Joint Doctor with an old Blueberry mother originating from Sagarmartha Seeds. The resulting plant is a vigorous, potent, autoflowering strain with excellent side branching. Although some of the blue hues from the mothering genetics have been lost in this cross this strain maintains the mothers fruity taste. It is indeed a hybrid, great catch! I’ve adjusted the recipe to reflect this change.


Introduce yourself
Recipes for Northern lights auto

Thank you very much for the quick answer… will the plant get too tall and burn the cola , if I don’t top it?


Hey Kirk,

I like to keep the plant 8-10 cm (3-4 inches) away from the light. Topping helps create more nodes a the top, and produces a shorter, bushier plant, which helps keep it away from the light. You can also ‘super crop’ your main stem if it’s getting too close to the light. This is basically pinching the stem, twisting and bending it to be horizontal. I’ll work on a more detailed post about it with some pictures. A final trick to combating height issues, is popping your coco pod through the lid. This can gain you several additional inches of space.


Coco pod pushed through

Hey guys, first Grow here and I’ve been super excited. The door on my box seems just a little off but nothing I was worried about for light or smell. Everything has been going awesome, I’m growing Northern Lights.

I’m on day 21 and I’ve noticed the brown rust looking spots on two bottom leaves. They are all also druping some as well. I’ve also noticed some brown stuff on the roots and in the water.


Hey @Darthgrobo

If you could take a picture and post that would be great. If it’s the very 2 bottom leaves you’ll be fine and you can cut them off. There is the following comment about it in the recent patch notes for the reciepe update below. :point_down:

Welcome to AG, happy growing!


Hi @Darthgrobo,

Sounds like some root rot may have snuck into your system. Here is a great article explaining what it is and how to avoid or fight it. The brown spots should be taken care of with the recent pH adjustments, allowing more Calcium/Magnesium to be absorbed.



![image|375x500] Here’s a picture to get a better look



already cut the bottom 2 with the spots


Your girl is not happy. Is that browning in the roots, or just the light? If so looking like root rot. Take a look at the link Stephen posted above!!


Yea, she has some browning. Not sure what happened. She was doing so well. I ordered a humidity gauge to see how that is. My room sometimes gets a bit warmer at night.

I’ve ordered one of the things to treat the roots as well. Hopefully she’ll perk up



Definitely looks like root rot there - follow Stephen’s guide in fighting it off




Hey Stephen,

Thanks for the help. I ordered one of the chemicals to treat the root rot. Not sure how she ended up with it. The only thing I can think of is it maybe gets too warm in my room. Do you suggest maybe moving her to my living room? If so, I would just unplug her real quick, move her carefully and plug back in? Thanks so much


Hey @Darthgrobo,

Yeah, a high temperature in your reservoir invites pythium (root rot). Moving the unit to a cooler spot would help. Good luck and keep us posted!