Old topic but wanted to share my input. I'm growing hydroponic tomatoes (various strains) at university in a lab setting (indoors under HID lights) and outdoors in a greenhouse. In one of my greenhouse NFT systems, i recently had a similar problem on 1 tomato plant (total 9 plants that share the same res and tubes). But im gonna try to diagnose your issue by mentioning what others missed out on. 1 major cause of leaf curl is compaction of root system (i.e. roots are compressed or dont have enough space to expand). This risk is exacerbated in hydroponic systems that use tubes. This was the problem i had and had to replace tubes with square tubings that have a liftable top. Once you have access to roots, you must seperate them strand by strand (i.e. so they arent sticking together). In your setup, this risk will further be exacerbated because you filled the entire pvc tube with hydroton (right?). Remove hydroton from tube and place the plant in a net cup with hydroton. Nitrogen burns usually cause browning/yellowing of leaves (similar to sun/heat burn) and not purpling. Test your solution for each chemical if possible, or use a commonly employed aggregated measuring device that shows total concentration in ppm (dont let it exceed 2500). In my system, only one plant was affected. Coincidentally, it was the largest of all plants with the most root mass. I let another normal one grow to its size to see whether it would undergo the same problem, and it did. Viral and bacterial infections that cause leaf roll usually cause it to roll up. Same with the physiological roll. If your leafs roll down AND if your stems bend, this is caused by a diminishing turgor pressure (read: not enough water reaching afflicted area). Mist several times when lights are off (no photosysnthesis) and observe increasing turgor pressure (unbending). Or, untangle roots and remove hydroton from from pipes. I tested various growing methods including fully and partially submerged roots. They all work but a submerged root cannot intake oxygen; it has to borrow oxygen from another part of the plant (i.e. a root part that isnt submerged or above ground stem). This requires energy for transportion and isnt the most efficient (optimal) way for growth and cellular processes. Lastly, an airstone in the reservoir is useless unless the reservoir is completely airtight all the way up to the plant holes. Better to keep small airstones in the pipes right under the plant roots. Those that say aerating the res prevents bacterial development.. is false. If you dont have air in res, you will get anaerobic bacteria (they grow/accumulate slowly but acidify the solution); if you have air in res, you get aerobic bacteria (not acidifying but grow extremely fast). Most bacteria prefer aerobic environments for optimum growth.

I just ordered some PEX (cross linked polyethylene) piping to run a line about 125-130 feet back because I am sick of lugging long water filled hoses around. The cost is as follows: (2) 100 ft rolls of 1/2 inch PEX piping $60 (1) Crimping tool and SS clamping rings $33 (3) 90 degree elbows $8 (1) Tee $3 (1) Adapter for 3/4 fitting to faucet to 1/2 NPT 'SharkBite' fitting $5 (1) 1/2 inch SharkBite ball valve (for drain) $7 Total $116 This will give me a hose connection set on a post (existing) about 120-130 feet away from a faucet that has a fitting for two hose connections with individual shut offs. When done with watering I would just crack open the drain line and shut it off at the house. Of course if any drip or soaker hoses are desired or need the cost of these extras would have to be added. I figure for $116 and maybe a day's work on installation. I will leave it on the surface covered in mulch in some areas and bury it in a shallow trench in other locations. I don't see any need for a deep trench, it is simply a hose substitute. An engineered irrigation system is another story, of course. The PEX is very inexpensive, once you have the crimping tool you have it forever. PEX is rated for potable water and freeze 'resistance'. The line will run all downhill in my case so it will be simply drained for the winter and drained after each use....if I remember. ;-] It is rated for more pressure, far superior freeze protection and is an easier installation (IMO) than flexible PVC and certainly standard PVC. 160 PSI rating at 74 degrees (tested to 480 PSI). Minimum bend radius for 1/2 inch tubing is 4 inches so it can be sent in a tortuous path where needed. 1/2 inch is fine for me and it will be easier to bury and more flexible. I would think it would be plenty for an average size drip irrigation system. It is available in various sizes up to 1 inch and for cold, hot water and for radiant heat systems with different tubing ratings. It sure as heck beats dragging around 150-200 feet of hoses up and down hills and all over the place. I my case it will not be near any utilities and extensions would be easy if I wanted them. FWIW Jon

Can you retake those pictures on a cloudy day or in the morning before the sun hits it (no flash)? You are watering too frequently. You should be watering more like once every week or two (YES, once every 7 to 14 days). But you should be deep watering when you do. Here's more... Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall. Second, you should be mowing at the mower's highest setting every 7 to 14 days. YES, every week or two. Tall St Augustine will grow much deeper, more drought resistant, roots. I have been very successful getting rid of fungal disease in St Augustine using ordinary corn meal at a rate of 20 pounds per 1,000 square feet. Apply to the entire yard because it will create green spots if you only put it on the fungus spots.

gardening is an art.. not a science ... and when you make it into a science.. imo.. its just no fun anymore .. i dont understand.. with the vagaries of mother nature.. and her weather.. how you could expect anyone to come up with a system of what you should do in your yard.. in your soil.. with your ambient weather ... and surely minimal winter temperature.. zone.. has nothing to do with winter watering .. so why are you fixated on that ... temperature is one of lest important WINTER issues.. dont you think?? also.. if you were somewhere where you actually had a winter.. i would tell you that dormant plants dont need much water at all.. but i surely dont know z9 nor CA... but you need to take that into consideration ... do your plants even go dormant for winter??? .. teach me something ... ken