You can do that, but over time salts will build up in your soil. The salts will damage your plants. The salts are mostly left-over fertilizer.

If you water that way, then you will have to occasionally water your pots very heavily, so that it "flushes" all that built-up salt out of your soil. I'm not sure how often you will need to do that.

After you water heavily, you will need to do something to drain the extra water out of your pots, because it won't drain out on its own. Tipping your pots at a 45 degree angle might work - more water drains out that way.

Taking the whole thing out of the pot, soil and all, and letting it sit on an old towel until a lot of that water has been absorbed is better - but only do this if you can lift the whole mass of soil out of the pot without it falling apart on you. If your plant hasn't yet grown enough roots to hold all that soil together, this method won't really work.

I’ll also add that not all potting soils/mixes are equally bad. As is the case with all things, even if there’s something “great,” it doesn’t mean other lesser things can’t work be good enough.

For example, I can grow virtually anything I’ve tried in ProMix (though I have to be careful with succulents and with repotting every year or two religiously, mixing with a lot of perlite), while I can’t keep weeds alive in Miracle Gro, with or without perlite. Others, however, manage fine on MG. Go figure.

Also, as someone who eventually grew near everything both inside and outside in variations of gritty mix in CA, I’ve repotted many of my outdoor guys in NV into Fox Farms potting mix because I need much higher water retention in the soil between the 4% humidity and 110+ weather—and actually having a life where I don’t want to and cannot water daily. Of course, now I water very infrequently (1-2 drenchings a month in spring or less than 90 average, or once a week in summer when it’s 90+?) for most of my succulent pots.

So, depending on your climate, your temps, your plants, and your habits—and IF it’s a relatively decent potting mix—then I’d say yes, you can use it, expecting to trial and error.

If i water far more rarely, do you think that it would be better?

You will have to water more rarely if you use that soil, or you will drown your plants. It will not be better than using a better soil.

I think i will try to add 50/50 perlite to this soil again as adviced before.

And I will need to water rarely as you said.

What kind of soil do you have, exactly?

the label says %

25 compost

25 peat

the rest is organic matter etc

no perlite or vermiculite

Yikes. That sounds like it will be...sludgy. (Quickly, not immediately.)
If you’re planting veggies (one season), you can give it a go. But I’d not plant anything valuable or long term in it, if using a container. Quick edibles might fare fine so long as you use discretion when watering, which you should do in any container. :)

Or, if you have any ground to plant in, it sounds wonderful to mix up with native soil for a veggie garden.

Good luck!

I have peat and vermiculite.

I am planning to add vermiculite because it is light and it adds to aeration but it has high water retaining capacity.

I dont know what to do.

some people say vermiculite retains more water but gets the extra water of the soil and thus prevets saturation.

I thought to add vermiculite because of this. But as you said, adding just perlite will be better.

Thanks for all your comments and advice.

You don’t want to add anything that’ll retain more water.

Dont use vermiculite for anything. Perlite is far more superior for the task.

I have decided what to do with your great advice and comments.

I will upload my photos in the future if i can be successful :)

I will buy perlite on the internet.

Vladimir advised me to buy coarse size perlite. But i had read that using small and big ingredients together wouldn't be a good idea.

The smaller parts would fill in the blanks between big ones and the mix would be something like concrete.

I will order perlite tomorrow, what do you say as a final advice?

Normal small perlite or big one?

Get coarse perlite, but standard will work if that's all you can get.

I would up the ratio of perlite to soil mix to 50-50. Your mix of compost and peat is exceedingly moisture retentive all on its own, so adding vermiculite will only add to the problem. And once fully saturated, vermiculite collapses and compresses, further impeding drainage and aeration. The perlite (pumice works equally as well) will retain its shape so continue to assist with drainage and aeration.

Watering 'rarely' can be problematic. You need to water as frequently as necessary to address the plant's needs. That's why good drainage in a container planting is so important........it allows you to water as often and as fully as necessary without creating overly wet conditions that will lead to root rots.