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Yellow Sprouts -- something is wrong

Posted by runswithscissors 4/5 MT (My Page) on
Mon, Apr 1, 13 at 22:58

I have a whole greenhouse full of sadness. My germination rates this year are terrible, and of those that are up, they are sick.

Growing medium: 1/4 peatmoss, 1/4 coir sawdust, 1/4 vermiculite, 1/4 compost. (plus some perilite for plants prone to damp-off.

Greenhouse is kept about 65 degrees at night but soars up to 100 degrees during sunny days....but I open door and turn on fan. Still it stays hot.

Seed flats are kept on soil heating cables at 70. Plus I have shop lights for un-sunny days.

Water is adjusted to 6.5 ph.

The sprouts break the surface and then sit there. After a few days they turn yellow and wither away. If I can coax them to make a true leaf then we're off and running, but that stage is a challenge to reach this year. I don't believe it is the heat because the greenhouse has had heat build up every spring and this is the first year I've had these symptoms. I know PH affects nutrient uptake so I've adjusted water to 6.5.

Any ideas? When is it safe to give the first shot of micronutrients? Before germination takes place, should I water with, say kelp water? I spent alot of money on seeds for this year...and so far, very dissapointing. Perennial seeds mostly, some annuals. My worst babies to live are annual vinca...what could be wrong with these little buggers?

Many of my seeds required a chilling period which I provided. No sign of delphinium, anemone, penstemon, grasses, .... or even petunia or can a petunia NOT sprout?!

Follow-Up Postings:

RE: Yellow Sprouts -- something is wrong

There doesn't seem to be anything in your choice of ingredients for the medium to promote rapid draining and porosity; not the peat moss, not vermiculite, not the coir dust and certainly not compost. Plus, the temperatures are way too high. Unplug the heating cables and adjust the temperature in the greenhouse.

I guess you don't have roof ventilation...all of the heat goes straight to the highest point and just stays there unless able to escape. Have you considered purchasing some shade cloth?

So...I'd say that there are two factors that are working against you. Uh Oh, what kind of containers did you use? Maybe three factors.

What are you fertilizing with?

RE: Yellow Sprouts -- something is wrong

Several things working against you that I can see in the info you provided.

Your growing medium is very poor and probably the primary factor, the temperatures in your GH need to be much better controlled both night and day - 45-50 at night no more than 65-70 in the day, having plants sitting on soil heating cables just cooks roots - they are for germination only, and you are probably way over-watering too given that mix.

Add pH adjusted water which isn't needed and can cause additional problems, and now "nutrients" to be added to the mix which will only compound the problems.

Transplanting them to a proper balanced growing mix, better GH management and avoiding over-watering would prevent most of your problems but it may not be possible to save many of the existing plants at this stage.

I'm sorry for the problems but many valuable lessons can be learned from this.


RE: Yellow Sprouts -- something is wrong

I have thought that over, and over-watering may be a problem, but my mix dries out so fast now, and it dried out even faster before I added coir to the mix. Montana humidity is extremely low, (I live in a "high desert".) What mix ratio do you recommend? I hate buying pre-mix formulas because they are the same ingredients we can buy separately and mix together for alot less cost. I can easily go thru 50 or 60 lbs of mix a season.

The heat....the dang heat....I know that is my biggest problem! It could be 26 degrees outside, but as soon as the sun rises the inside becomes an oven...(perhaps my high elevation has something to do with it.)

Last year I tried shadecloth, but it did not help. Since we get far more un-sunny days than sunny ones, the cloth made everything grow very leggy. And, altho it did cut down on the sun-rays it did nothing to stop the heat build-up. I keep the vents taped up because all the heat escapes during the night thru them if I don't. I cannot afford to heat the night air by untaping them until the end of april or so.

When some seeds in a flat have germinated, should I turn off the heat cables? I use humidity domes too, but if I don't the mix dries out overnight.

Regulating the temp in the grhse has been hard because the ambient temp may be one thing, but over on the shelves where the seeds sit, it is much cooler. But I'm thinking my judgement on "heat" may be humanized instead of plantized. If I'm standing in the greenhse and the thermometer reads a cool 65*, and I shiver, does that mean my sprouts are shivering? Would putting the fan on at night swirl the heated air around, or will it simply cool the air and blow it over already shivering plantlets?

You guys are right....HEAT....I live in the mountains of Montana and heat is my worst enemy. I'm cooking my babies, aren't I? Can you give me your idea of what "heat" to us, translates to "heat" to a plant? Also, what is dry? If I touch it and it does not feel moist, is it actually moister than I think? If the top is bone dry, does that mean that 1" down it may be okay?

One last note....all my veggies are thriving. My tomatoes, peppers, and greenhouse cuke are doing well. I dug up a bell pepper plant last fall and overwintered it, and got 3 good peppers from it so far and right now it sports about 8 more little ones. The seedlings that I started in Feb are all about 4" high and very healthy.

Thanks so much for your help.

RE: Yellow Sprouts -- something is wrong

I hate buying pre-mix formulas because they are the same ingredients we can buy separately and mix together for alot less cost.

I'm sorry but that just isn't accurate. It is much more complex than just stirring together random amounts of ingredients. Quality commercial mixes are based on well-researched recipes, carefully pH balanced, and have wetting agents and stabilizers added to them and then sterilized. Cost is relative if one makes their own mix but then loses all their plants, right?

Professional quality mixes such as ProMix BX and Metro Mix 360 can be purchased in whole bales for much less than the cost of the equivalent number of bags of components and have 3x the benefits. So no, I can never recommend making your own seed starting mix. Make your own growing mix for established plants if you wish, but not for seed starting.

GH environmental management is a science and managing differs greatly from house to house even when they are right next to each other like mine. Automatic, thermostat controlled systems is the most effective way to accomplish it but even they have limitations and can be expensive.

You can learn much more about GH management over on that forum rather than here but you need to do everything you can to stabilize your temp range without sacrificing light exposure. The ideal goal for growing plants is no less than 45 at night and no more than 65-70 in the day. Germination trays are kept in a separate enclosure in the GH to allow for increased soil heating and yes the flats are removed from soil heating ASAp as germination begins. The remaining will either germinate shortly or they never would have anyway..

Auto systems include such things as auto sun screens set to a thermostat that unfold and contract as needed, sectional sunscreens that provide heavier screening on the west side than on the east or overhead rather than on the sides depending on how the house is situated, auto vent openers, auto exhaust fans, evaporative coolers on thermostats, auto heaters if needed, etc. In other words the more automatic you can make the systems the better.

Hope this is of help.


RE: Yellow Sprouts -- something is wrong


Thanks so much. What you say makes sence. Germination mix is alot more important than growing mix, isn't it?

45* at night....Really??!! Brrrr. And keeping the hse at 70* or below during the day would be impossible with the set up I have now. I need to revamp my whole seed-starting process starting with temperature management, don't I? Automatic everything would be very cost prohibitive, so I need to figure out something. It makes sence too, what you wrote: greenhouse operations have different sections for germinating and growing...I'm thinking of turning my spare bedroom into a small germination room, and leave the greenhouse just for growing on.

Thanks again.

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