Do you have any seed-starting tips to share?

[angelinaottawa]

The only seeds that I germinated that does need heat is coleus.

Important: Never ever put your coleus seeds on heat mat. Two batches of mine were fried and not a single one sprout. Of course, fried seeds don't germinate.

Coleus seeds can be germinated under light, no heat needed. My coleus were just sprinkled on top of the soil mix, 90% germination rate as well.

Coleus seeds = needs lots of light, no heat please.

[styric]

When you have seeds on top of an old fridge, don't believe the information packet that says sprouts in 14-21 days. Six days in, I've got inch high babies..

[Elena Zimmerman]

It must be the old fridge specific. I think that advice about the top of the fridge is outdated for new fridges that are better insulated On the top of my fridge, all I was growing was mold, and the sprouting was slooow.

I can't believe how fast everything growing on the heated mat! I only turn it on for the night time. My basil went from poking through to having those 2 first false leaves yesterday. Holy cow. The best $37 I have ever spent!

[styric]

I have two fridges. I have a newer fridge that is very insulated so useless, and I have a second old fridge from the 80s. That is the one I use.

I'm serious about how fast it works. These are litchi tomatoes and they have a 14-21 day germination (IF that). This is six days in when I moved them to under the lights:

[Elena Zimmerman]

Sprouting times with heat mat:

cucumbers and melon: overnight and outgrowing the jiffy top in 2 days
tomatoes (grape): 2 days
petunia: 3 days
hot peppers: 4 days

[CdnChelsea]

I use warm water when watering my seedlings. Cold water would be quite a shock to them.

Instead of digging up the grass to make a new garden, I lay down some cardboard; making sure it overlaps. Then I add compost, grass clippings, leaves and some good soil mix up to about 6". After I do all this, I put a thick layer of mulch on top so the soil won't dry out.

[Elena Zimmerman]

I am having a lot of problems with fungal activity this year, it killed a lot of seedlings for me. I used a different starting seed mix last year (Schultz) and had no problems. I will go back to it next year, to see if that was at the root of the problem. Cinnamon'd the last batch of seeds this morning, but in the past it didn't help. Oh, well.

[styric]

Try tea tree oil in your water if you don't have cats

[Elena Zimmerman]

Thank you, I will keep it in mind for next year. This year, those that made it, made it, the rest... didn't. Heh. Luckily, our freakish winter made a huge amount of seeds to sprout right in the beds, from the flowers that normally are too gentle to self-seed here (like marigolds, ). Wee!

[growitall]

Elena, for annuals (e.g. flowers, vegetables), it's very appropriate to start the seeds indoors 8-10 weeks before our last frost, so that they are a good size by planting-out time (after hardening-off, of course). Light is the determining factor, since not many people have sufficient light set-ups to allow starting them - and keeping the seedlings healthy - for longer periods than this.
For perennials, it is preferable to start many of them much earlier, specifically those whose seeds require pretreatment, specifically, stratification (varying temperatures) to induce germination. Stratification can take many months, and more than one temperature cycle (warm-cold, or cold-warm) can be required. (The need for stratification is almost totally restricted to perennials; extremely few annuals require stratification.)
I know that there is much anecdotal talk about the effectiveness of heat mats for seed starting, but there's no scientific proof that they enhance germination with most species (see publications of Dr. Norman Deno - his three volumes on Seed Germination: Theory and Practice). So long as your environment is near room temperature (~70 degrees F, 20 degrees C), there's no advantage - I see seed germination happening within days for a large variety of perennial species when started at room temperature - there is nothing unusual about it (though it is really neat, for sure!) To be clear, heat mats are useful though if one is starting seeds in a cold environment such as a very cold basement or unheated greenhouse.
Another seed-starting technique that can yield results that seem almost magical is scarifying the seeds of pea family members (e.g. lupins, lathyrus, oxytropis, astragalus). "Scarifying" means to rough up or penetrate through the hard seed coat by rubbing on a file or nicking with a sharp blade. When the scarified seeds are then planted in moist medium, you can sometimes get germination overnight which is great fun too!