Well everyone time for my next journal installment. This one will take you through the begins of crop steering. Hoping to remember to grab my Aroya sensor tomorrow so I can take some new dry back readings but I’ll run you through where I am at.
I am on day 9 of veg these are my calculations for what I’m doing with watering. As soon as dry down begins happening regularly (5-8 days usually) I begin watering to signal vegetative growth. This essentially means 2 hours after lights come on I initiate the first feeding. Over the next 1-2 hours I am trying to work my way up to Max water content in the block. I use small blocks so I am trying to do it in about an hour. I know my blocks fully saturated hold about 68% water content. My current 14 hour dry back (2 hour after lights on till 2 hours before lights off) gets down to about 45%. This means I am losing about 23% of the volume of the cube in water over that period. A 4x4x4 rockwool block is about 1049 ml. So that is a dry back if about 241 ml in 14 hours. Or about 17 ml/hour. Why this is important is it I ran only 17 ml of water to my blocks each hour water content would never increase, so this much be factored for in these calculations. If I continue keeping water content near saturation until two hours before lights off my dryback overnight by dryback will be from about 68% water content to only 58% water content meaning to work my way back up I need give 10% (104.9 ml) of the volume of the block in the first hour + what it will dry out in that first hour (17 ml) total 121.9 ml. To prevent channeling I irrigate every 15 minutes max. This gives you 4 irrigations in the first hour of 30 ml each to work back up to field capacity. Then every few hours as dry down happens I bring it back up to capacity with a little bit of runoff all the way until two hours before lights off.
I would always recommend checking flow on drippers to ensure everything is working correctly. To do this I ran 30 drippers into a container and ran them for 30 seconds. I ended up with 300 ml of water. Meaning each dripper is emitting 10 ml of water every 30 seconds.
This means I will run my irrigations for 90 seconds 4x in the first hour of irrigation. This will bring me back up to field capacity and then by giving additional pulses as dry down occurs I am able to signal vegetative growth. I am going to flip any day now (really holding the entire thing up for a white truffle I added in 2 days ago to catch up).
When I flip I will begin signaling generative growth throughout the stretch which will be completely different timing.
You would initially think this constant watering would build up salt in the block and EC would rise but it is really the opposite. Frequent irrigations prevent the massive EC spike caused by dry downs.
I’ll try to find my glasses to take pictures through as the fluence light fucks my camera up into oblivion and the only solution i have found is to shoot through the glass lense. Also will bring the Aroya by to get updated dry down readings. Every day as your roots grow these things change so as a grower you are doing your best to hit a moving target.