I've blown up a few dual arc bulbs using my digital dimmable ballasts, but regular HPS bulbs work fine on them.
Combination MH/HPS lights really are not necessary anyway, so no great loss.
The dimmable feature is nice for someone like me who can't move their lights in relation to their plants and doesn't want to shock plants coming straight from fluoro tubes to 2400 watts of light - starting them off at 50% really helps them ease into their new home.
meh... I put clones, which have been under fluoros for about 14 days, straight into the flowering room under 1000HPS with never a problem.
hay DR. Al ,just built a box hor my mom's under a 4 foot eight bulb flo. just wanted to say thanks and you were wright about everything. my 6 mom's are in hydro farm buckets. lol they took off like a bat out of hell. thanks al. i will put post pic's of my mom's before i take cuts
I hope fluoros are enough to raise your mums. If you're running a perpetual/rolling harvest system where you need cuttings every couple of weeks, you'll need a fair amount of light power to regrow them within that time span. I don't generally recommend fluoros for anything but clones, because they only need to be convinced it's daylight for 18-24h/day, instead of needing a lot of light for photosynthesis.
Al....... Thanks for all your knowledge over your countless posts. I am usually more of the trolling type, but every now and then a question pops up that I can't find a straight answer to. I am very well versed in plant physiology and soil culture, but I am new to the hydro scene. I am still trying to pinpoint a reservoir management strategy that is effective and easy. Work smarter, not harder right?
Yep.
I dont employ your perpetual system, opting to instead grow fewer, larger plants. I have 16 grape stompers under 4 1000w HPS (4 per light) in a CAP Ebb & Gro system w/ hydroton. I am using GH nutes following the Lucas method (sort of....i am actually doing 3G/5M/15B ml/gal for the first 2 weeks of 12/12 before I take the Grow nutes out). I keep the reservoir at 40 gallons by topping off every day with fresh H2O (plants are using about 5 gallons per day right now...Day 11 of 12/12...flooding 4x per lights on and nothing in the dark). As you can imagine, my EC tails off rather quickly with each slug of H2O I add. I seem to get equally valid opinions about topping with either straight H2O or with nutrient solutions of various strength (Lucas says full strength, some say 1/2 strength, some say 1/2 strength every other day....). Either way, I would like to try to stretch out my reservoir changes to the longest interval as possible without sacrificing plant health.
I'm not a fan of this Lucas stuff.
You should never add nutrient concentrate nor freshly mixed nute soln to an old tank of nutes. Use the nutrient mfr's instructions for mixing. If you follow the mfr's mixing instructions, you'll get the NPK ratio the mfr specifies. A partially spent tank of nutes may (for example) have half the N, 1/3 of the P and 2/3 of the K remaining. If you add nute concentrate or premixed nute soln to the tank, you're not going to get the mfr's specified NPK ratios. You may end up with more of one and less of the other. Ratios that are out of whack can cause the appearance of nutrient deficiencies, but they're not deficiencies at all. You wind up chasing your tail and cooking plants.
When topping up tanks, you might dip your TDS meter into the solution and add plain water until the TDS comes to the point it should be at, 1000ppm or so. The NPK ratios won't be at the specified ratios for a fresh tank, but you'll be shooting low instead of high. It's always better to underfeed than burn. You can recover a plant from underfeeding- you're much less likely to be able to recover a cooked plant.
Should I aim to maintain a target EC, or allow the EC to drop over time? What is an acceptable drop? Again, the Lucas method says to drain and refill the res after 1/2 the original volume has been added back. That would mean every 4 days for me, which seems a bit much. Any guidance you offer is appreciated....thanks.
It's preferable to maintain a target strength. Most nutrient mfrs will tell you something similar as regards changing the tanks when 50% of the volume has been replaced with plain water. If your nute strength is dropping precipitously when topping up, just don't top the tank up fully.
You might also consider a larger res tank. 5L per plant is is about right. I use 125L tanks with trays that hold 24 plants. The nute strength will stay constant, within about 10%, as the soln level drops, over a 2-week life of a tank of nutes. In other words, the plants are eating the nutes in a similar proportion to the quantity of water they're using. I don't have to top up at all, just add H2O2 every 3-4 days, then dump, clean & mix new sauce at the 2-week point.
Thanks.
