So I watered the plants yesterday afternoon to about 3 times out, the width of the plant and gave them over a cup of water each and already today, sticking my finger down into the soil, it’s dry as far down as my finger will go. They likely dried out because of the sun and not because the plants are drinking that much. With the top 3 or more inches of soil being that dry already, should I water again today or wait for the plants to droop a little? There is likely moisture down lower in the pots.
These are Autoflower plants (4 different strains) that are being grown outside in 5 gal. fabric pots. I used a pump sprayer to water them so that the water just didn’t run right out.
The 2 larger plants popped out of the ground about on June 1st. One of the other ones came out a few days later and the smallest is a week behind because the first seed didn’t germinate and I had to start another one. Are these plants small for their age? (18 days old for the larger ones, 14 days for the next one and about 10 or 11 days for the smallest).
First, a pat on the back for sticking with it so far. You are doing well.
One major criticism though... sticking your finger in as far as it will go. It came out dry to no surprise. Yes, the sun has a lot to do with this process, but as an experiment, set a fully watered bag of soil out in the sun and see how long it takes it to dry out all the way to the bottom without a plant in it. You will be surprised. But consider this. The water you have been giving has indeed been helping the plant, because you are pointing the water to right where the roots are developing, within that 3x circle. But that which is not immediately sucked in by the roots in the top and middle of the container, has to drop down to the bottom. Gravity works. There is now a small pool of water down there, and this smart plant has grown some strong feeder roots down into that wet area. Things are going well. The plant knows what it is doing.
So look at your plants. Do they look stressed? Are they wilting? Are the leaves drooping or are they joyfully reaching upwards toward the light?
You know what causes the plant to be able to lift up its leaves and track the sun? Water pressure. The more leaves and the taller the plant, the more water pressure it takes. Apparently, even though your dip finger came up dry, there is water there somewhere. The plant is NOT complaining, only your dry finger is. The reason your plant is so happy is that all of the roots down to where the water table starts, where the rest of the way down is under water, all of those roots above the top of that lake are getting oxygen! Oxygen is just as important as water, and your plants are deliriously happy because they are getting the best of everything right now.
I doubt you are qualified yet to be able to tell a true "I need water" droop and one caused by time of day. The true look of a "I need water" droop starts in the very lowest leaves and visibly moves up the trunk over the next 12 hours. It is a very specific type of droop, but thankfully there is an easier way to tell when it is time to water. It is also not necessary to water immediately when seeing that droop... I always wait 12 hours. It is far better to let the plant need water so badly that it is starting to droop, than it is to water early. When the plant starts to get desperate, it grows new roots looking for that water. By forcing the issue, you are forcing the plant not to be lazy, and grow new roots. This rootball thing doesn't just happen by accident.
Your goal is to pull oxygen all the way down to the bottom, using the top of the water table as a diaphragm to suck the air down deep into the soil. The ONLY way to do this is to be patient and aware enough of where that water table is, so that you don't water until you can see that it gets down into that last inch or so of the container. Please note that the very tip of your dry finger was nowhere near this, and could not possibly tell you what you needed to know to determine if it was time to water.
The three most common and accurate methods to tell that it is time to water are either the "lift the pot" method, the weighing method, and the dipstick or probe method. I personally like the $6 hardware store moisture meter probe that will show you exactly where the water has settled to in the container (the top of the water table).
Anything less than using these methods to be sure how much water is in there, is just guessing when to water. You have taken all this effort so far not to overwater, and your plants are doing great because of it. Keep with me here. Autos start strong for a week and then stall out for a week or so up top, while the roots really get going, and then they flat out take off. Yours are about to do that. Just keep with this watering thing. Very soon you will water to runoff, and then it is going to be 7-10 days of torment before you need to water again. You are going to have to learn this new skill to determine how much water is left in that container or you will quickly loose the advantage you have gained so far. Also keep in mind that as you have been watering to 3x the diameter, you have been giving more and more water each time. You would be surprised how much water is building up in the bottom with just the meager amount of watering you have been doing... and those roots are getting stronger and stronger, and I bet you are starting to see almost exponential growth up top.
You are almost to the next stage. Then we will do another trick, and water small amounts around the outside edge every 3 days to entice lateral root growth, while waiting for the exponentially growing plant to drain the water in the bottom.
