I've had a much easier time not putting them in a zip lock where they're squished between paper towels or a filter, but just using a shallow tupperware container with some paper in the bottom. Seeds are then just placed on top of the wet paper, and the container can either be closed by its own lid or (since I lose those lids all the time) place the whole container in a fitting zip lock bag.
This has a couple of advantages :
- mark one corner of the container, and you can germinate many varieties in the same container in a very small space, utilizing even smaller heaters. Just draw out a map of your container so you know which is which (I usually take a photo with phone or tablet then edit it in some software that allows adding text to images, so literally write the variety name on each bunch of seeds)
- it's much easier to check for germination without disturbing the whole package. in zip locks you have to get your hands in, introducing fungi, then futz around with wet paper (a bit easier if it's a filter but still), often the roots will catch on both sides if germinated and since you can't see you'll break one side off etc etc. In a container with a clear lid or even easier if it's in a ziplock, you just tap the top so the condensation clears and you see what's going on with your seeds. You don't even have to open it.
- it greatly reduces the occurrence of helmet head. as they germinate they are still in a very moist environment. they will lift off the bottom but the shell won't dry out so they get rid of it without problem.
- once they germinate they can easily stay in there for days,even longer than a week if you don't have time to pot them. just don't put them in a very light spot. they will open up cotyledons then just kinda stay at a certain height and wait. since they straighten out it's very easy to pot them on, provided you take care not to break the roots. you can avoid roots catching on paper if you put a layer of baking paper on it and then seeds on top. baking paper actually gets wet easily. not butcher paper, the whitish baking kind.
- the general and biggest advantage of both of these paper methods is that you don't waste space with pots and seeds that are dead. that and the fact that most varieties will take around a week to germinate. often less, very rarely 10 days or more.
i use this method for germinating most stuff i grow, except tomatoes and tiny seeds like petunias.
This (paper zip lock) is actually called the Deno germination method, after the late dr. Norman Deno who dedicated his scientific career to testing out thousands of plant species and finding optimal germination conditions.
Since his death his work went into public domain and can be found here:
book:
https://naldc.nal.usda.gov/catalog/41278
first supplement:
https://naldc.nal.usda.gov/catalog/41279
second supplement:
https://naldc.nal.usda.gov/catalog/41277
