As you can see, I had already trialed with some shiso seeds (as shiso is just one of those things I can't have too much of and can easily give away -- not to mention having a million seeds) -- and they have germinated. In fact, they look pretty good.

I attempted this because I had a recent failed attempt with something bizarre happening to the shiso cotyledons (shown below in red circles) and eventually, they all died. The only thing I used in these that I don't normally use was vermiculite, but plenty of folks use vermiculite that it's hard to correlate this flop with that particular ingredient. I never did find out what happened -- does anyone recognize what this cotyledon browning syndrome is?

Anyway - that provoked me to try seeds in a completely "pure" medium - and now, I have these seedlings in pure Turface, excepting the 1mm of screened potting soil I put on top to keep moist. That means....it has virtually no nutrients at this time, correct?

So, in contrast to my other seedlings in potting soil blends I made -- these require a bit more attention and fertilization, I would guess. Or am I wrong? Ordinarily, I would not give them anything other than water and sunlight until they're transplanted.

Any guidance would be much appreciated!

-Grace

But I can address some possibilities based on see germination in general. Shiso, like most other culinary herbs, requires no special treatment and is normally quite tolerant of most growing conditions except for excess watering. Single seeds in such a large amount of soil (or whatever) can often lead to germination root rot.

However the most common cause of "browned", unhealthy, diseased cotyledons is infected seed. The second most common cause is soil fungus - one of several - that can exist in unsterile soil/potting mix and are encourages to develop in overly moist conditions.

I would speculate that a third possible cause would be simple sun scorching since these are apparently being germinated outside in direct sun. Cotyledons are easily burned by direct sun.

As to the feeding question - most seedlings do not require any supplemental feeding until they are transplanted to their final growing place. It is done as a comfort to the grower, not for the plant. They definitely do not require, and do not tolerate well, any supplemental feeding prior to true leaf development.

If the grower wishes to feed a supplement to seedlings that have developed at least 1 full set of true leaves then it needs to be a very mild, well-diluted fertilizer used sparingly.

Hope this helps.

Dave

I always just figured max sun possible for the seedlings, especially when it's not that hot right now. 72 tops? That or soil-borne reasons sound feasible; I am relatively certain it's not the seeds themselves as I have 6 from an earlier sowing that all made it and 12 more coming up right now without problems, so far, in pure Turface. But after reading your suggestion of sunburn, I peered into my seedlings in Turface and I kind of see some browning similar to that previous batch, as shown below. Does that look like sunburn possibly?

Agreed on the feeding seedlings, but I guess I am more concerned solely because Turface has no nutrients vs. my regular seed mix would have some. I made a really weak batch of Foliage Pro in water (1/2 tsp for 40 ozs) in a spray bottle and spritzed them yesterday but perhaps this, too, is unnecessary.

But yes, I realize that I wouldn't get many replies to this in terms of what to do. :-) but now I've learned I can burn my seedlings! :-)

Susan, I never got any feedback re what it might be! (And to be clear, the green sprout was the normal one; the brown ones were the oddities, haha.) I have strong shiso going right now (6 weeks plus?) so I am really inclined to think it isn't the seeds themselves. But having said that, I'm still at a loss. I'd heard of damping off, but thought it affects the stems first. The stems remained upright and green until almost the end when they withered away and disappeared. The leaves changed color to brown while looking healthy in texture but towards the end, they dried up. Most bizarre. But in the end, dead is dead, and these were dead dead dead. Boo!

I dunno -- this whole "planting in Turface" is new to me! It just seems to me that compared to other mediums, it contains nothing so I feel like I should supplement.

I did notice, especially today, that the growth is very strong and erect compared to the first batch which was in a peat + perlite mix. Those turned out nice but I can't say they were particularly lovely seedlings, I pulled one out of one cell which had two pop up and there's one really thick, white and straight root I stuck that one into a pot of shiso already going.... So far, impressed with Turface fines!