How to water pot in grow bags

I’m attempting first grow. I’m doing mostly OK. I’m trying to get my head wrapped around watering. I would like to know how much water? I am using ProMix as my growing medium in 5 gal grow bags. How often? How do you know when it is enough/too much? What kind of container do you use when watering? Do you water first then add fertilizer, yes I know to Ph correct my water.

1 Like

How much to water is based on each environment, age/s of plants, Rh, Temps and age of the mix. ProMix comes organic and potting soil version. If it is OLD, the micro-organics will have broken down some of the nutrients. Being a heavy foundation of Peat, the ph is low and calcium is added to buffer / bring up the ph. Peat / coco, similar - do not have the nutrients that soil carries so nutrients are added as are amendments.
IMHO -as a long time grower, I listen to my plants and they tell me when it is time to water. Overwatering is one of the easiest things to do…It flushes nutrients, creates blocks and causes all kinds of issues that usually get coined as “nutient issues”.
Wet to dry…When you plant, your medium is usually dry before you place your plant in the container. Lift your containers, plastic, cloth, whatever, and get the feel of a dry container.
We tend our plants on a daily basis, sometimes even more than once a day. You will see if they are under watered. The plant will droop (a great time to tie down some branches if you have not trained it) and you feed (water or nutes). You cannot really overwater (you can flush if you go to far but adding nutrients will bring things back) but you can water TOO OFTEN. Depending on the size of the container, it will drink a a few pints to almost 2 quarts. The plant will respond by PRAYING (leaves stand upright, like hands folded in paryer). They love that…then you let it go until it begins to droop again, then water. That is wet to dry…
Watering is also different for the stage of life. I start seedlings in small containers. They need nothing but water for the first 2/3 weeks. The soil has nutrients and feeds them. Better organic soils will feed longer. When we grow autoflowers in an organic or living soil, we usually can disperse with nutrients until they begin flowering. Photo period plants are different. Autos begin to flower in 4 to 5 weeks of sprouting. Photos will stay in veg state until we adjust the lights to 12/12. We usually veg for 8-10 weeks or more. Again, look at the plants, they will tell you when they are hungry and thirsty. In an organic soil, I usually begin feeding at 5 to 6 weeks. If my plants look healthy and growth is good, I hold off.
Fertilizer - wet / dry
dry fertilizers - usually we TOP DRESS…add some fertilizer to a little soil / substrate and work in the top inch. Top dress should only take place once every 4 to 6 weeks
wet - Mix (and if using multiple ingredients, mix each ingredient separately) and aerate before feeding
Then there are amendments - Molasses, kelp, calcium/mag, etc…another story


Mike, Thank you so much. I’m good about no nutes the first 2/3 weeks. Thanks for the info on how to do the liquid fertilizer and how to top dress. I’m using fresh Pro-Mix and I mix it with better soil that I buy from a nursery. Local soil is clay/caliche. I have a nice photo-period vegging. I have started training. One question, you say aerate before feeding, the mix you are feeding? or the soil? Thank you for all the help. This is awesome.

clay - caliche …sounds like me…In Vegas…all the dirt is clay and caliche… I did a box using 5 yards soil plus about 10 bags compost (Kellogs) to start…So I got dirt with a caliche base…lol :laughing:
If I feed liquid nutes, or tea, even just watering, it gets areated and Ph tested before use
I am a little weird that I also aerate the containers at times. Like when they use those machines to aerate a lawn…I poke holes and insert an air tube. As we water and soil ages, it compresses. When it is hotter (and if you got caliche, you know hot) I water more often and my soil compresses. I just do this when I am not aerating liquids…make use of my air pump. I made an attachment for the end of the air tube…

1 Like

Mike, thank you so much. I live in New Mexico, yes I know hot. You just answered a couple of things I’ve always wondered about soil aeration. What you are saying makes sense to me. I grew up watching farmers, my dad always aerated his soil before planting. At the time this didn’t make a lot of sense to me what he was doing, now a ah ha moment. Thank you so much. I just retired and haven’t thought about growing except tomatoes and flowers. This has really expanded my understanding how to grow.

im using 5 gal fabric bags, & been using 1 gal of water each time, I just started filling a 5 gal bucket with 2 gal of water/nutes & just setting the fabric pot right in it for about 2 min, & it still takes about a gallon, & keeps the surface dryer… seems to work good, but im still a beginner & very high. welcome & happy growing!

1 Like

I love your idea of just setting the bag in the water. I’m using 5 gal bags, that would work well for me. I’m attempting to grow my own medicine and lower my costs. This isn’t covered on Medicare, it will be a great day when it is! Thank you for all the help. Buying another bucket.


just keep in mind the bag will weigh about 8lbs more when you lift it out. Im currently suffering with a back injury, so this is important just in case you have a bad back… Happy growing Beth.

Thanks for the reminder Mike. My case, I’ll have to be careful for the shoulders also.
Enjoyed chatting with you. Have a great day Mike.

1 Like

Hi Mike,

This is a follow-up. Thank you for your suggestion. I found a deep saucer that holds about 3 gal and put my girls in there. The lift isn’t so strenuous and it lifted my grow to new heights…wow
Thank you!

1 Like

im glad it worked well for you Beth, happy growing :slightly_smiling_face: