Premier ProMix, hand-shredded a bit.

I use flint based chick grit.

https://www.amazon.co.uk/Chick-Flint-Grit-25-kg/dp/B00NE4GI0K/ref=sr_1_15?keywords=chicken+grit&qid=1692442199&sr=8-15

I mix it with a loam based substrate and also use it to topdress pots. For fine seed, I sow on top of the grit and water with a fine rose. I always use the flint based, not the mixed or oystershell. Best value ever.

this link: https://www.epicgardening.com/best-seed-starting-mix/

says: Seed mixes are typically finer and lighter than typical garden potting soil, making them easier for young roots to navigate.

rocky grit sure seems counterintuitive....

generally: https://duckduckgo.com/?t=ftsa&q=seed+starting+medium&ia=web

i dont recall.. specifically.. what i used 20 years ago ... but it was fine milled ... the babes were quickly moved out of it on the first repotting..

ALWAYS sterilize your media first... i used to use the microwave for small batch.. and the oven for large batch.. a alum turkey pan covered in foil... like a giant jiffy pop... when you see steam.. its hot enough.. kills weed weed.. reduced future algae.. and all bugs... just no downside if working in the house...

https://tipnut.com/sterilize-soil/

ken

I use a pro mix for starting seeds. I probably wouldn't use sand or grit unless it's a plant that tends to grow in that kind of medium as a mature plant. What kinds of seeds are you starting?

(Sorry in advance for the OT remark @SeniorBalloon)

I use flint based chick grit.

I am sure we have had threads about this before i.e. it seems "chick grit" is much more readily available in the UK then say in Canada. I dont ever see it at garden nurseries (if it is it would be sold in very small quantities). I bet I would need to go to a farm supply store to be able to get it in a large bag.

I've used chicken grit in the past to help prevent damping off. There's little risk of that when using a good quality soilless mix. You should be able to find chicken grit online in quantities sufficient for seed starting use.

My comment was not as clear as it could be. "Grit" in this reference is only a top dressing over seeds that require being covered. No more than a 1/4 inch covering over the seeds of some kind of rocky material made up of 1/8th inch pieces.

@rosaprimula I have read that some use chicken grit. It's usually sold in very large bags, and I only need a bit. I purchased some aquarium rock and will give it a try. Will keep my eye out for small bags of chicken grit.

@rougue Off topic posts are always welcome. :o)

Thanks,

sb

Nah, I don't use sand or grit for that. It's more of a visual aid for the gardener to see where the sand is and where the seedlings are going to be popping up. It's not necessary for the seeds or seed growth itself. I just use more pro mix on top if it's in a seed pot. Or just use fine garden dirt if it's in the garden. I just take a bit of dirt and let it dry out and crumble or sive it up fine if I need it really fine. If it's for carrots (most often I see the sand trick for carrots), I like to use the board over the seed instead of using the sand cover trick. Works great, helps retain the moisture till they pop up and then easy to remove the board after.

I also just use the potting mix I'm using to the start the seeds as a cover or if direct sowing, the garden soil, if the seeds require it -- many don't, they are simply sown on top of the growing medium.

I bought some Jiffy seed starting mix yesterday for some cuttings I have to take, I've been wanting to try this because I've had some trouble the last couple years with the potting mix from the local nursery I've always gotten. I'll have to keep an eye out for the Pro Mix, I don't recall seeing it locally but then again I've been loyal to the stuff I've been using so haven't really paid attention.

You can buy it in much smaller quantities, Senior balloon. I do get through a few 25kg bags over a season because I use it in my containers for permanent planting, where drainage is a big consideration. Tbf, I often reuse my soil mixes for seeds because they have been leached of fertiliser (most mixes have a base fertiliser which lasts around 6 weeks). I run the soil (such as my spent tomato mix) through a riddle then add a bit of perlite or vermiculite or whatever comes to hand really. I have been sowing seed all my gardening life and have become far less prescriptive about the precise composition of the substrate, as long as I can maintain a reasonable level of moisture and there is no danger of drying out and practically having to submerge the pots in order to re-wet them (such as what happens with high peat mixes). The grit helps to keep the surface at a stable level - vital for tiny seeds which are not covered with a potting mix. I have used fine 'horticultural grit but have found chick grit to be my most economical soil amendment. I don't think there is a perfect mix which is guaranteed to work - you are always adjusting the watering levels (I try to water from the bottom after the initial top watering to settle the seeds into the soil and grit interstices). I rarely buy a specific mix for seed starting but have always preferred to use a mineral based loam rather than soilless composts...I don't think this is an exact science and I will use what I have to hand. I have always top-dressed the soil because I have hard water which can leave a calcium carbonate hard pan on the surface (I never manage to keep special rainwater for irrigation.) so the fine grit is pretty much the only thing I am consistent about.

For cuttings, I am even less fussy - have used anything from pure sand to hydroleca granules and nearly everything in between. I would say go ahead and try various methods. I rarely sow all my seed at once - will hold some back in case of fails or just to try a slightly different method or mix, including direct into an outdoor nursery bed. The most important thing is to remember that nothing can grow while still in a packet

In our winter we purchase sand/gravel for traction and I have used that as a thin top-dressing to help with, say, fungas gnats .

Looks like this... in 10 lb bags I think?

@rosaprimula Are you saying you mix the grit in with the soil? In reading your post it sounded like you were using it for both purposes, as an amendment and as a top dressing for seeds. Thank you for the detailed post.

SB

I use chicken grit for just about all my potted seeds. If I were a more attentive seed-sower I might skip the step but since most everything gets sown and forgotten for a few days (at least) the grit has saved me many a time.

My rule of thumb is maybe 1/4 inch grit on top and then sprinkle especially fine seeds on top, 1/4 inch or less on top of anything papery or fluffy (windblown seeds like dandelion or clematis), 1/4 to 1/2 on top of most everything else, and 1 to 2 inches on top of bulb seeds such as crocus or daffodils.

Anyone who has ever tried to keep a gravel walk weed-free would probably agree that its an excellent seed starting surface.

Most of my seed-starting runs Dec-Jan and I just put the freshly sown pots outside to sprout whenever.