Soil for growing from seed?

[Wulfskaar]

What soil is best for growing trees from seeds?

Is it better to use species-appropriate bonsai soil, peat, or something else?

I have used peat because it came with some seeds I got as a gift, but I'm wondering if there's something better?

 

[Pitoon]

What soil is best for growing trees from seeds?

Is it better to use species-appropriate bonsai soil, peat, or something else?

I have used peat because it came with some seeds I got as a gift, but I'm wondering if there's something better?

Anything that holds moisture, but drains well will work to germinate seeds.

 

[LittleDingus]

I usually use something finer like coconut coir of even miracle grow. Some seeds need to push themselves up from under the soil so nothing too heavy for them. I occasionally use DE (NAPA 8822...oil dry) but generally prefer something like coconut coir for most seeds.

 

[atlarsenal]

I do most of mine in jiffy pellets.

And then transfer them into 3 1/2” pots.

I have done some directly into small pumice.

 

[Wulfskaar]

Thank you! This is extremely helpful!

 

[Wires_Guy_wires]

My general purpose mix is 1:1:1 potting soil, sand, black peat.
A top layer of shredded sphagnum sometimes.

But it takes a different style of watering compared to bonsai soil. Shallow trays for the win.

 

[Shibui]

you can already see there are lots of possible ways to start seed.
For me it depends on the species I am germinating.
Larger seeds and very easy to grow species like maple, Chinese elm, Oaks, etc just plant in any good potting soil or even straight into bonsai mix.
Smaller seed require a finer particle size or the seeds can wash deep into the soil and won't make it to the surface. I use the fines sifted from bonsai soil or a seed raising mix for these. eg Melaleuca, Callistemon, Eucalyptus, etc
For difficult to germinate and species prone to fungal infections I use a more sterile mix. Commercial seed raising mix is OK for most as it has been heat treated to kill pathogens and weeds.
A mix of peat and perlite or pumice is generally fairly inert and suitable for most seed types and can be mixed to suit your own conditions and watering regime.


Please note that commercial seed raising mixes have little or no nutrient included so it is important to start feeding seedlings soon after they emerge.
Mixes with finer particles stay wetter than the soils we are used to. Watering as for your bonsai may encourage fungal disease so adjust water as required to maintain damp but not soggy conditions. Crowded seedlings and lack of air flow also encourage damping off fungus. Sun and moving air are 2 of the best antidotes to fungal problems.

 

[leatherback]

I do most of mine in jiffy pellets.

Do you break the substrate in them after adding water? I start tomatoes & peppers in them, and I find they often have dificulties penetrating the substrate.

When transferring them into larger pots, do you remove the pellet substrate?

 

[Lutonian]

Jiffy pellets suck for bonsai there a pain to remove from the roots, there good for veg or plant that there is no need to remove the from

 

[LittleDingus]

Do you break the substrate in them after adding water? I start tomatoes & peppers in them, and I find they often have dificulties penetrating the substrate.

When transferring them into larger pots, do you remove the pellet substrate?

When I use jiffy pellets, I do stir them after hydration to break up the compacted soil. I grow tomatoes and peppers in them just fine.

For my bonsai seed, I'm a bit random on if I clean off the soil at repot into a bonsai mix or not. The amount of soil is trivial and tends to wash away over time. I do wash off more often than not...often depends on if I'm trimming tap roots or if the roots are exceptionally fine or...

 

[LittleDingus]

Jiffy pellets suck for bonsai there a pain to remove from the roots, there good for veg or plant that there is no need to remove the from

Stairring them after hydration to break up the compaction makes it significantly easier to remove them from roots. Do transplant before the roots grow through the mesh if possibly.

 

[Yamabudoudanshi]

I've been using fine akadama with good results.

Depending on volume and availability though, I'm sure it could get expensive.

 

[Lutonian]

Stairring them after hydration to break up the compaction makes it significantly easier to remove them from roots. Do transplant before the roots grow through the mesh if possibly.

I tend to use bonsai soil fines or commercial seed compost and perlite 50/50 for bonsai seedlings, if there is no need to remove it from the roots like for veg & landscape plants rockwool works to but has the same issues as jiffy pellets.

 

[atlarsenal]

Do you break the substrate in them after adding water? I start tomatoes & peppers in them, and I find they often have dificulties penetrating the substrate.

When transferring them into larger pots, do you remove the pellet substrate?

I usually soak a flat or two at a time in a five gallon bucket overnight. When I am sewing my seed I squeeze the excess water out of each pellet individually. I do not remove the substrate when transfer them into 3.5” pots. It gets cleaned out the next season when they go into 6” pots. I do remove the mesh containing the substrate though.
@Lutonian you are absolutely right when removing the roots from mesh on the newer version of jiffy pellets which is some type of fibrous material. You pretty much have to use scissors. I use the old style jiffy pellet which is a delicate plastic mesh which tears very easy. I was lucky enough to find a large lot of the old style a couple of years ago but I just used the last of them last weekend.
Here you can see the jiffy pellet substrate which I believe is probably 50/50 peat/ coco coir.

 

[Wulfskaar]

When I use jiffy pellets, I do stir them after hydration to break up the compacted soil. I grow tomatoes and peppers in them just fine.

For my bonsai seed, I'm a bit random on if I clean off the soil at repot into a bonsai mix or not. The amount of soil is trivial and tends to wash away over time. I do wash off more often than not...often depends on if I'm trimming tap roots or if the roots are exceptionally fine or...

I was thinking the same... that when the time comes, I might not bother to remove the peat from immediately around the roots. I imagine it would wash away quickly while protecting the roots during the repotting process. I'm just so afraid of breaking the tiny roots and ruining the seedling. I still have a way to go before I do this though.

 

[leatherback]

I'm just so afraid of breaking the tiny roots and ruining the seedling

Yes. The roots are delicate. But they are not so delicate that you cannot handle them if carefullOnce the first real leaves show up usually the roots will have developed enough to no longer work like little britte glass spikes but more like thin cotton thread. Just an FYI

 

[Shibui]

I'm just so afraid of breaking the tiny roots and ruining the seedling. I still have a way to go before I do this though.

No need to be afraid. Seedlings are programmed to grow roots. If some roots get broken they just grow new ones. Even species that are really difficult to grow as cuttings have no problem growing new roots as seedlings. I routinely snip roots off seedlings to encourage better lateral roots. Often that means cutting nearly all roots off. Sometimes a seedling is accidentally broken above the roots but I have discovered that is no a problem. I just plant the broken stem (top part) and more often than not it will grow new roots even without any special treatment. seedlings are really resilient so do not worry about breaking a few roots.