This is how I have them set up on the heat mat with thermostat under fluorescent lights and checking on the soil temperature with a thermometer.

And these are some new chilli seedlings just come up on the right which I'm hoping will turn out better!

Happy spring, Australians !

I have found that purpling tomato and pepper seedling is quite common. I think 2 factors may cause it, ambient temperatures and the amount/intensity/duration of light. It may also depend on varieties. Some get purple some won't (!?)

I am curious, do you run the heat pad 24 hrs a day or is it on a timer with the lights? I am not an expert but I have had some success staring from seed. I read an article from NMSU that talked about optimal day and night temps for successful germination.

Total shot in the dark, but if its on all the time maybe they need to cool a little in the evening hours?

Might be worth taking a couple off the pad at night to see how they compare. I don't think 60 is going to hurt them.

dj

It's hard to tell from the pic, but is that soil mix wet? What mix are you using in the starter cells?

Edit: Already answered:
> "The seedlings are in soil blocks made with 3 parts compost 2 parts coco peat and 1 part river sand."

I'm not familiar with coco peat. What is the particle size?

Any idea what the pH is? IIRC, peats tend to be alkaline and that could be decreasing nutrient mobility. Any fertilizer in the base mix? Applied to the seedling flat?

Dennis

This post was edited by DMForcier on Wed, Oct 8, 14 at 15:54

I have never started peppers with a heat mat, ever, and have never had a problem getting anything to come up.

However it is common agreement that once the seeds have sprouted, the heat mat is removed. Good soil temps for germination are not good for developing roots.

4 fluorescent lights create way more heat than you would think. Now that I have a thermostat (I have always gone commando starting seeds, eg just the lights, the flats, and me to water and turn them off and on) I find that if I don't turn the fan on, temps just above the soil will easily get over 100F (it hit 104F, then I got nervous and switched on the fan).

4 T8 fluorescents in 2 fixtures, each fixture is 7" wide - so my bulbs aren't that closely spaced and there aren't that many of them. This may explain why for over 60 years (combined between my dad and I) we have been able to start seedlings of any sort sans heating mats. I imagine the old T12s put out even MORE heat.

I'm building a thermostat controller for the fan to turn it on at 95F and turn it off at 80F for the tropicals I have currently in my flats. I will be able to set that to whatever is appropriate for other crops later, but for now - I have curry leaf plants that I am coddling along.

If you don't have a fan in your set up, you may want to add one. Heat really can build up fast under those lights, in that small space just above the seedlings. And definitely lose the heating mats for any flats that have already sprouted.

I like the big long tray - but that has a built in thermostat? What is that?

Thanks everyone for your replies!
seysonn: ThatâÂÂs good to hear the purplish colour is common! I tried searching for pepper seedling images at that size and could only find green ones :-)
djoy: Yes, I have the heat mat going 24 hours and just switch the lights on and off on a 16/8 hour basis. Being a complete beginner, I did a search for the optimum temperatures and was going off 29 (85) for germination and around 27 (80) once they are seedlings with a warning not to let the temperature get below 18 (65) or I think somewhere else said 15 (60). ThatâÂÂs the tricky part with our house not being very well insulated, I canâÂÂt be sure it wouldnâÂÂt dip to like 10 degrees (50) during the night. Maybe I should try taking them off the heat mat during the day when they have the warmth of the lights + warmer daytime temperatures and then pop the heat mat on at night when I switch the lights off?
DMForcier: coco peat is coconut coir/fibre. It is meant to be a sustainable alternative to peat that has the same properties of increasing the water-holding capacity of whatever you add it too. It comes in âÂÂbricksâ to which you add water to hydrate and it expands tenfold. IâÂÂm not sure how to describe the particle size of it though?
IâÂÂm not exactly sure how wet the soil blocks are at the moment. IâÂÂm paranoid about overwatering now and have now left them unwatered for 4 days. I canâÂÂt really test by sticking my finger into the mix because the soil blocks would just fall apart since they donâÂÂt have a pot around them to contain them! I have picked a couple of them up, they feel lighter than initially when saturated, the top is definitely dry and further down they look darker and feel cooler and more moist purely going on the feel from the sides.
IâÂÂve tested the pH of the mix and itâÂÂs neutral. I havenâÂÂt added any fertiliser at all as I was waiting until they had two sets of true leaves to repot them and fertilise then, but they seem to have stopped growing! Is there any rough guide on a timeline for growth once the seeds have germinated?
zensojourner: thanks for the information regarding the heat mat. I had read that you should only use the heat mat for germination for tomatoes (which probably explains more poor tomato seedlings that ended up dying, I had them in the same tray as the peppers and kept them on the mat at 85 degrees!), but I thought that the peppers and eggplants need that heat right through the seedling stage.
IâÂÂve just started using a fan because I read that it can help with stem strength, but have so far only given them an hours âÂÂburstâ with the fan on a couple of times. How long would you have the fan running? I do think that the lights I have a giving quite a bit of heat. I started some other seeds without the heat mat and just below the surface of the soil it was reading 22 (72) degrees +. I havenâÂÂt...

I've pulled three of the seedlings out of the tray to take a photo of the soil blocks side on. I think you can see the mix being very dry at the top, but darker underneath. Do I wait until the leaves are drooping down to water again? A lot of the cotyledons are pointing up or crossing over themselves. It also seems that there are white little roots growing out of some of the soil blocks (2 inch size) which makes me think that I should maybe try potting them up into bigger pots? I'm just a little wary of what mix to use, in case it is my mix that is causing problems! I planted these seeds on the 10th September and they germinated within 1 week.

The heat mat should be removed (or turned off) when the seeds sprout.

Little white roots could be roots, or they could be fungus. Probably the former. But they're not too big to stay in the block. Root hairs are a good sign.

To me the leaves (cots) look yellowish and possibly crisping. In other words, not particularly happy.

Neutral pH is not great. You want a pH below 6.0 or even below 5 - peppers like acidic soil. I won't try to give a lesson on soil chemistry because I don't know that much about it.

> "coco peat .. is meant to be a sustainable alternative to peat that has the same properties of increasing the water-holding capacity of whatever you add it too."

Compost has *plenty* of water holding capacity. It doesn't need more. You should be adding things like perlite to provide guaranteed oxygen to the roots so they don't drown. Large particulate size aids in drainage and prevents the dread "perched water table" where the soil acts like a sponge and holds water, drowning the roots. This is the theory behind 5:1:1 container medium (which I don't use for seedlings).

That said, you appear to be very conscious of the dangers of over watering. And your seedlings do not show signs of it. Well done.

At this point I'm thinking that there's an issue with nutrients - perhaps even too many. How well rotted was that compost? What was it originally? Manure?

Dennis

The compost I used is a bagged compost. I can't find what is was originally made of, but this is the description:
"Richgro Organic Compost is a fully composted blend of activated organic ingredients to provide your new or existing garden, including vegetable garden, with a boost of natural organic nutrients.

This will ensure strong and healthy plants and vegetables.

It can be used all year round and an application at the start of Spring and Autumn is highly recommended.

* Complete with added soil wetter
* For all plants and veggies
* Organic Input"

At this point I've taken them off the heat mat, but am worried that they might be crisping (my tomato seedlings started at the same time advanced through yellowing and now the cots are brown and dropping off...). Is this a point of no return? Is it better to just start again? Or try repotting them into a different medium?

So difficult doing this for the first time! I'd like to figure out what part of my setup isn't working so I can get it right next time :-)

I like that little glass plate! Would you believe I have one JUST LIKE IT! I don't know where it is right now or I'd grab a picture, LOL!

Anyway. Not to go against the common wisdom here but I swear those little seedlings look UNDER watered to me. If you wait 'til the plants droop to water, they are already stressed. The point is to avoid stressing the plant.

In future I would recommend against using that mix for seed starting - I believe I read it was compost, coir and sand.

For one thing, never in my life have I ever bought a bag labeled "compost" that actually was. So whatever was in that bag - it almost certainly was NOT anything one would normally think of as compost.

My seedling mix for decades was peat and medium grade vermiculite (I used coarse for potting, but medium for seeding).

I can actually get medium grade vermiculite still, but I used to sift the fines out of coarse for my seeding needs and since I haven't been able to get the coarse any more, I've virtually stopped using any vermiculite whatsoever, just because I have no use other than seeding for the smaller grades of vermiculite. I may reconsider that. But here are some of the seeding mixes I typically use:

• 1:1 peat and vermiculite (medium is ok for seeding, but not potting)

• 1:1 peat and good quality bagged SOIL such as Miracle Grow (again, of limited use as anything other than a seeding mix or single season container mix)

• 1:1 peat and very fine pine fines - I'm concerned this may end up too moisture retentive but we'll see.

• 1:1 peat and Scott's Turf builder - this is very finely graded pine bark with a teensy bit of fertilizer - 1-1-1. I think this could be a good replacement for my old mix of peat-vermiculite. I don't know if you can get anything like it in Australia.

I've also successfully seeded in any halfway decent bagged soilless potting mix. I do try to avoid coir because results with coir tend to be so variable.

Also, for all the bad rap peat gets for being "hydrophobic", the few times I've worked with coir I've found it to be next to impossible to rewet if it dries out. If you went 4 days without watering that could be an issue.

What I would do at this point in your position is get some seeding paks or small pots and "repot" those seedlings. Try just a couple at first and see how they do, but they look stressed enough to me that I don't see a lot to be gained by waiting any longer than you have to.

BTW - purpling of LEAVES is not anything normal for pepper seedlings. I have never seen that. Maybe I read that wrong. What I HAVE seen is that the stems of seedlings will sometimes darken to a kind of dark burgundy or purplish colors. I tend to see that on seedlings that have gotten leggy. It fades after awhile.

I have some basil seedlings right now where just ONE seedling got leggy because it sprouted before all the others, I had them in a south-facing...

zensojourner: thanks heaps for the detailed response. I do think I will try repotting these as I just don't think they are doing well, especially since all my tomatoes are dying!

By the way, the stems of all of my capsicums, chillis, eggplants and tomatoes are purple bar three which have green stems. So perhaps there is something wrong with the mix nutrient wise?

Its just so hard to know since I think I've done so much wrong! i.e. too high temperatures, overwatering initially.

I think it's almost getting to late for me to start my seedlings, but I will continue to see if I can get it right as a learning experience if not for next year.

I'll repot some of these and see if they can be rescued and I'll also start off a new small batch in some bagged seedling mix. Just so I can see whether I can get my light and heat mat setup working otherwise :-)

Already answered.

This post was edited by green-passion on Mon, Dec 29, 14 at 12:25

I forgot to answer regarding the capillary mat. So I definitely didn't know the purpose of it starting out :-) but the heat mat that I have is made of plastic and it came with this felt mat that lies on top of the plastic and there is a note on the heat mat that reads: "IMPORTANT: the capillary mat (felt) and soil must be kept moist at all times". Hence I was spraying both the mat and soil several times a day to keep everything moist until I panicked a few days ago about overwatering and have since left the soil unwatered but continued to spray the capillary mat.
But I definitely don't think I was using the mat properly for the soil blocks. I have the soil blocks sitting in a "flat"? tray which has little holes in the bottom so water can drain out. I had this sitting directly on the capillary mat. But I did the watering from the top. The soil blocks have held together well.

IMO under watering has not been not a chronic issue with these seedlings, though you may have done it recently. So long as the bottom of the block is moist, the little white roots will get down there and get the water.

I use commercial potting mix (Miracle Gro) not soil, though others here use the soil. If you are careful there should be no issue with water retention.

I'm with the zenster on this: Give up on the soil blocks. No peat pellets. No "instant nursery" kits. Just seedling starter flats or little pots.

No heat mat after germination. BUT, that leaves you with a problem. Some guys bounce up immediately; others stay in bed until the sun is high. When to turn off the mat? SOLUTION: Start your seeds with the paper towel and baggie method. Check the Pepper FAQ for a description, and instead of weak tea use 3% hydrogen peroxide. When a seed sprouts, move it into the starter mix, about 1/2" deep. That way the heat is only under the germinating bags and never under the starter cells.

It's not to late to start again. And/or again.

Dennis

I have to say this before I forget - if you are using capillary matting, you CANNOT use a heating mat. A heating mat cannot be submerged in water. The capillary matting needs to hang down into a reservoir of water to do its work.

The only way you could use it would be to have a platform large enough to keep it out of the water (and you need to keep the cord out of the water as well), put the capillary mat on top of that, then the soil blocks on top of the capillary mat.

In the first place I think this is still unsafe. But in the second place, what will happen is that the heat from the heat mat will just dry the capillary mat out and mess up your watering. If it doesn't short out, it'll DRY out.

I never had this issue when I was using soil blocks because I never used a heat mat. I don't think the two can go together.

But if you are using a heat mat, there are solutions for the issue of seedlings that come up at different rates.

I have these deep root cell paks that I really like in a lot of ways, but they are solid, un-separatable flats of 72 cells each.

I have never used a heating mat before in literally decades of seed starting. If you are using overhead fluorescents that are properly spaced (eg an inch or so from the soil surface) I don't think you generally really need a heating mat. At least, I haven't. So the issue of removing seedlings from the heating mat hasn't been one I've had to face before.

But now that I have a heating mat I will probably use it, at least occasionally, which leaves me with the dilemma of staggered seedling emergence, and differing germination rates for different plants if I'm direct seeding into my deep cell 72 pak that doesn't come apart.

This is my solution:

There are a LOT of plug trays out there like this, but most are a lot larger - typical full flat size (roughly 9x22-ish).

Now at first they may cause you to cringe over the whole "but it's STYROFOAM" non-environmental thing.

Except these things will last virtually forever with minimal care. A lot of the plastic paks only last a season or two. These things can last decades. And when they do finally give up the ghost - which will be a long time - they are fully recyclable. That's pretty green to me.

I like these because now it doesn't matter when a seedling germinates, you can just pop the germinated seedling out of the cell and pop it into a regular cell pak or pot. Or even a soil block, if you made it with a deep enough hole.

The ones Parks sells are allegedly designed to use with pre-made plugs - but you do not have to use the plugs, just fill it with a good peat-based potting mix, tamp it to firm, seed, and you're good to go. The roots and the peat will hold it together when you pop it out.

If some of it crumbles out as you transplant it, its no big deal. Loose crumbs don't matter, just the main root mass and that will...

> "Also, no offense - perhaps I misunderstood what I read above - but the idea that seedlings will send rootlets down through dry soil to get to the moist bottom layer isn't really an accurate way to look at how seedlings get started."

Not how they get started. They have to be moist in order to germinate, so one must presume that they germinated in a moist block. The *first* thing a seed does is send down roots, then erects its cots. Now that the block has dried down to the level described - i.e. in their current condition - there are roots to utilize the moisture that remains. The seedlings have not lost turgor, so QED.

My own self, I prefer to keep the whole cell moist below a dry surface. It's not rocket science (to coin a phrase), and the plant will help you as best it can. But you have to be confident that you won't over water, and that's a function of the medium as much as it is of the practice.

Dennis

Well that's a little less frightening. It's my habit - which may or may not have a scientific basis - to keep the soil evenly moist throughout the growing period - seed to soil, as it were. (Hopefully not seed to grave, LOL!)

If you can water properly when they're germinating, the same watering method will work for the seedlings themselves, all the way up through container planting or placing in the ground outdoors.

There ARE some plants that benefit from drier soil or letting the soil dry out once they are mature - lots actually. Thyme, or rosemary, for example, spring immediately to my mind.

But while they're getting established, nearly any plant (that I know of) will benefit from even moisture. I like to water when they are getting dry-ish at the top, but not actually dry yet.

Plants are generally pretty flexible. Your method obviously must work just as well for you as mine does for me. So hopefully this is yet more evidence to the OP that she can and will find something that works for her, LOL!

BTW I came across more information on those speedling plug flats. I'm not sure how I have managed to never hear of them before. If I were still growing a huge garden, I'm pretty sure I'd be lusting after them. I'm lusting after them just a little bit as it is, LOL! But the little ParkStart thingies are more my speed these days.

Here is a link that might be useful: more about Speedling plug trays

Update on my poor seedlings! I "gently" repotted as best I could according to zensojourner's description into potting mix last night and they are all still alive a day later! I also repotted some into little jiffy pots without the net that I bought last night, but in afterthought I don't think they were the best choice as from reading they are just peat? But anyhow a few went into those as well.
Then tonight I started a fresh batch of seedlings in some straight seed raising mix I bought through a gardening club that I had used to germinate lettuce seedlings outside which I knew had worked well. I've just popped all of these on the heat mat and as soon as any start germinating I'll take them off the heat and put them under the lights. I've checked the temperature of the soil surface under the lights and its 28C (84-85F).

I've just put all the seeds into the same larger container and am planning to repot into individual pots once the seedlings have germinated and have one set of true leaves. Does this sound right?

One question, when I pot these (fingers crossed all goes well!) into individual pots, should I use the seed raising mix or switch to potting mix?

I'm also keen to read up on the method of germinating in baggie with paper towel. I don't know where I'll put all the seedlings if they end up growing well! I may put some in pots and have been reading up on the correct pot size and it seems that either a 3 or 5 gallon would be good for the chillis?

I've actually no idea exactly what chillis I will be getting as it is a mix called "Hellfire Mix" from the garden club :-))

> "when I pot these .. into individual pots, should I use the seed raising mix or switch to potting mix? "

That kinda depends on what you are re-potting into. I go from the starter cells into 3" pots. In those I use the bagged potting mix, but the whole contents of the cell goes in too, so I guess the answer is both.

Later I pot into something larger like 6" (and eventually into 3 or 5 gal or larger) and at that point I use a 5:1:1 mix, or whatever the ultimate mix will be. (5:1:1 has chunks of pine bark in it, and while it is very useful, especially where it rains a lot, I don't like to use it with seedlings.)

What the ultimate pot size is depends on the plant habit. Modest ornamentals like Numex Twilight can stay in 1 gal pots. Scorpions or ghosts you want in 5 gal minimum, unless you're trying to force an early crop. Given a vote, they would want 10 gal.

It's tough to grow from a seed mix. Knowing what the plants are make several decisions easier.

Dennis