Seedling Fertilization

[YumYum]

I'm looking for some information on liquid fertilizing my vegetable seedlings. I'm looking for the liquid ppm of N I should use to feed the seedlings and when to start and/or up the strength vs age. This is something I can't get a real clear answer from a search.

I have a very small homeade greenhouse that I use that holds about 1.5 flats. It germinates seedlings good but I've had problems with the new leaves being yellowish while the baby leaves are greener. I do like to turn off the greenhouse and open the lid on 55F or warmer days after they sprout to save electricty.

Should I be looking at a total ppm N per week and divide that by how many days I water/fertilize or just fertilize a certain amount every time I water?

 

[riverhamill]

I also grow seedlings in my greenhouse, and used to have the same problems with them turning yellowish. This is what I use and have had good luck for the past several years:

Dr. Earth 71115 1 lb 2-4-2 MINIS Root Zone Starter Fertilizer​

Once i was able to find this in liquid, but recently I have only found the powder. I just sprinkle it on the surface of the soil about the seedlings and water it in. It seems to work in eventually. I try also to dissolve this in water, but it does not dissolve all that well. But you might have better luck or be more patient and wait for it to dissolve. Let me know what you find that works for you.... Thanks

 

[YumYum]

This is what my tomatoes started out looking like. See how the new leaves are yellowish. The baby leaves weren't really affected.

In the background that is either broccoli, cabbage, cauliflower, or brussels sprouts (now planted) and they contracted a mildew, I think, and one or two shriveled up after planting, I'm guessing from damping off disease.

The peppers are not in the pic because I don't think they had come up yet but the tomatoes and peppers were planted at the exact same time and they have been side by side with each other the whole time and been through the same process.



The below is a pic from today. The tomatoes have mostly greened up although I can still see a little paleness to them. I think the tomatoes will be fine after being planted. They peppers however are very yellowish.



After most of the tomatoes and peppers sprouted I did move them inside near a window for maybe a week with 2 of these grow lights. Now I'm wondering if that created problems too since I don't think they have enough power/light to do anything, but not sure. The tomatoes and peppers are currently back outside in my little greenhouse. I tried to use those lights last year and they didn't seem to have enough light or something.

What are my plants missing or have too much of?
If anyone can point out anything else I'm missing, I'm all ears.

 

[YumYum]

I've decided to try an flush out the soil in case I've used too much fertilizer and maybe try to correct the pH if it is off. I really don't know if I've used too much fertilizer or not enough. The leaves never got real green before yellowing but I think I did start fertilizing a little too soon and possibly a little too heavy. So maybe I can eliminate those possibilities by flushing.

I calculated how much soil there is which is a flats worth of peppers. A whole flat is around 1 gallon of soil. I then adjusted the tap waters pH to 6.5 and 70 degrees F. Then ran 1 gallon of the water through the potting mix, waited 15 minutes and poured another gallon through them.

 

[DirtMechanic]

So what is in that soil you use? Once they start growing something that can help is magnesium sulphate. The magnesium helps uptake. Also for a nitrogen and calcium boost the calcium nitrate is water soluble. Something like osmocote might be a good thing. I notice that water soluble fertilizing tends to be on the weaker side and while it is aimed at indoor plants the rapidly growing veggies, especially fast growing hybrids, need more than I expect. I try to pot seedlings on into proper soil sooner rather than later. Even the little pepper sprouts develop huge roots really quickly and I would rather not damage them getting them out of a seed tray.

 

[YumYum]

I use Miracle Grow Potting mix. Not sure exactly what minerals are in it but I figured it had everything they needed. I've used ProMix and regular seed starting mix before and didn't really have any luck with those after they sprouted.

What dose magnesium sulfate would you give them?
Do they look like they are deficient in something to you?

I popped one of the little peppers out before I flushed them and it had good roots so I'd say all of the roots aren't harmed.

 

[DirtMechanic]

I start with 1\4 the mature plant or regular recommendend or whatever the instructions are and come up from there. A small plant does not eat much. Many fertilizers have magnesium, and I believe that soil you are using is pre-fertilized? It would be good to know. After all, you are thinking you have too much salts (fertilizer). It would not be uncommon to kill a plant with too much love. One tool a detailed person may care to use is an EC meter. This measurement is very often used in hydro but soil ec meters exist. At the least it would be educational, and inform future planning if something was found to be off in your current setup. But remember kids do not eat like grownups, they lose teeth and have intestinal adjustments as they find balance and so to do small plants go through stresses of growing where phytohormonal imbalances can produce seemingly odd results. In that regard Kelp may help or greensand perhaps.


Here are some of my Chile Nuevo that are all in the same repotting soil, old stuff that was outside a year, and the chorosis was random. Upping the nitrogen has helped new green leaves begin to emerge.

 

[YumYum]

I've been digging into the details of some of this stuff. I do need to examine the contents of the Miracle Grow Potting Mix.

I started out using this fertilizer:

Ultra Sol Water Soluable Fertilizer 20-20-20

20.00% Nitrogen 20.00% Phosphorus 20.00% Potassium 0.000% Calcium 0.000% Magnesium 0.000% Sulfur 0.500% Chloride 0.10000% Iron 0.05000% Copper 0.05000% Manganese 0.05000% Zinc Yes Sodium 0.02000% Boron 0.00100% Molybdenum

and when I saw the yellowness, I realized it contained no sulfur so I swapped over to this which didn't seem to help:

Expert Gardener All Purpose Plant Food 24-8-16

24.00% Nitrogen 8.000% Phosphorus 16.00% Potassium 0.000% Calcium 0.000% Magnesium 5.000% Sulfur Yes Chloride 0.15000% Iron 0.07000% Copper 0.05000% Manganese 0.06000% Zinc Yes Sodium 0.02000% Boron 0.00050% Molybdenum

We have pretty hard water here so I would assume there is ample calcium and magnesium in my water unless the plants can't use that form or something.

I've had this same problem before but I cant remember what type of seedlings but it was probably tomatoes and peppers. It is too early to plant them here, but if I could I think they would straighten up. I don't have any fertilizer/mineral problems after they go in the ground. Just happens with seedlings with me for some reason. As you can see with the tomatoes, it's like all of a sudden they came out of it and greened right up. The tomato plants are looking good right now.

I'll give them a day or two to see if the flush helped the peppers before I try upping the fertilizer.

Do you fertilize yours on a weekly or biweekly basis?

 

[DirtMechanic]

Just when they need water, and sometimes I am late. The solo cups get a hole poked in the side for drainage but I am not a good shot so they vary in height thus so does the reserve water. The form of calcium in calcium nitrate is immediately available, which is a bit rare for liming agents. Most get broken down by biological chemical activity in the soil or longer term oxidation but prepared soils are mostly dried at some point and or sterilized to some degree and lack a lot of life. Lime and eggshells and all that wont really work so well for the potting soil.

 

[YumYum]

Miracle Gro Potting Mix:
0.21 - 0.11 - 0.16

0.113% Ammoniacal Nitrogen
0.097% Nitrate Nitrogen

Derived from: polymer coated: ammonium nitrate, ammonium phosphate, calcium phosphate, & potassium sulfate.
and Ammonium nitrate, ammonium phosphate, calcium phosphate, & potassium sulfate.

In the state of Georgia, it is formulated from 45-55% processed forest products, sphagnum peat moss, peat, perlite, compost, fertilizer, and a wetting agent. The pH ranges between 6.3 and 6.8. It is designed to feed your plants for up to six months.

It doesn't state any other nutrients but it apparently contains ground up forest products (tree limbs and leaves) and compost so it should have all of the nutrients, right?

That sounds like a ton of nitrogen if I'm calculating this right:
0.21% N = 2100 ppm N by weight of dirt = 4200 lb/acre N.
Even though most of it is slow release, 4200 lb/acre of nitrogen sounds insanely high to me. That can't be right.
The potting mix is lighter than dirt so maybe that has to be figured in. Even if the potting mix is a quarter of the weight of soil that would still = 1050 lb/acre N.

 

[YumYum]

Here is what they look like at this point. Tomatoes growing great but have a little insect damage. Peppers still seemed to be stunted or something but growing slowly. They are greening up a bit on the right side.

Looking at my notes from last year the peppers stunted then too but then was fine after I planted them. Still not sure what I've done wrong. Another week or two and I'm going to try to get them in the ground so a late frost can kill them instead of me. Ha.

 

[DirtMechanic]

Starving them mainly. Start dishing the dinner to those youngsters!

 

[YumYum]

Starving them mainly. Start dishing the dinner to those youngsters!

Yea. I kinda got that feeling from the start but the peppers got the same nutrition the tomatoes did and still do, minus the one water flush to the peppers soil.

Tomatoes and peppers started at the same time but peppers germinated 1/2 week or so later. Tomatoes almost acted like they were going to be stunted and then all of a sudden popped out of it. I think the peppers will do the same now the temps are getting a bit warmer. Peppers are getting 200 ppm N twice per week now. Tomatoes, 125 ppm N twice per week.

 

[YumYum]

Update. Peppers are kinda coming around. I figured they would eventually but those are the tomatoes that were started at the same time as the peppers in the background. Me and peppers just don't get along. You can see a few that just didn't do much.

 

[YumYum]

I transplanted my peppers today. When the weather warmed up is when they started to unwind. I don't think they like 50 and 60 degree weather too much. Not that it kills them but slows them down.