I grow Nasturim in high % perlite in my mix and wasn't aware that they are sensitive to perlite. Do you have a source?

If perlite is on the bottom and below turface fines, why do you think perlite is the cause or the problem and not turface?

Perlite should be as "inert" as turface is (or more so).

I also have some sweetpea seedlings growing in perlite based potting mix outdoors now. They are still young and small but seem to be growing... some for a month now.

Hi, Filix. I hope you're doing well. ;o)

Perlite in volume can have ill effect on fluorine sensitive plants, but sweet pea is listed as 'somewhat tolerant' of fluorine, so if that's where you were headed, I'd tend to doubt it.

Did the plants that died appear to have a damping off problem? Do you think that perhaps you kept them too wet? Was the seed source the same? I'd probably tend to look more to cultural issues other than the substrate for the answer.

Take care. Have a good season!

Al

Yes that's where I was headed. They could have damped off. The seed source was the same. I planted 10 seeds in ten containers. Two of them were perlite on the bottom with turface on the top. The ones that died were in the perlite. The perlite is much courser than the turface,I mean like the size of a pea. I started them in this to prevent damping off. But it's still posible I kept those two a little too wet. I read that sweet peas like a slightly alkline medium. When these get about six leaves I was thinking of adding a little dolomite lime. Just a quarter teaspoon. Sound ok?

I will plant some more seeds in that perlite with turface on top, to make sure it wasn't me.:>)

greenchem your right they are both "inert". I can't remeber where I read about nasturiums being perlite sensitive. Thankyou very much. hope you have a good season too. filix

Sounds good. To help prevent damping off, you could also water with a weak tea of chamomile, too.

Do you feel like you're making good progress, Filix? It sounds to me like you are. Strong work! You've come a long way since you started posting here. ;o)

Al

Yes Al. I feel I have made a great deal of progress. You and others here have gave me such a shot in the arm. I think your three threads helped the most. Just learning how soil works made other things make much more sence.

Case in point...I took a few cuttings from my climbing hydrangeas and sweet autmn clematis this past spring. Instead of planting them and taking a chance with the small amount of roots they had, I decided to grow them on in some fast mix I learned from you. I wanted to keep them somewhat cool. So I grew them in my drybox. "a plywood box about the size of a small coffin with a 75 watt light bulb to keep my musical instument wood dry" It kept the inside about 50f. I'm taking them outside on somewhat warm sunny days above freezing. The dry box is out in my shop/garden shed with no other heat. They are growing beautiful, the clematis is a monster, with huge root system.

I know I have so much more to learn, but that's life. Thanks for all your help. filix