When I looked at the photo, what came to my mind was, is this plant getting enough sun? jennifer, can you tell us where the plant is situated?

I sincerely apologize for the delayed response! I never got any notification of replies to my question so I assumed there were none. I came back on here today because I have a new problem with my marshmallow. I have got them hardened off and they are all outside near my patio. They are definitely growing better but in the last few days, have all gotten purple leaves (still only a very minor issues with the yellowing)! It is only effecting the oldest of the leaves so far but the stems have turned purple too so I'm worried that whatever this is will make it to the beautiful newer leaves as well. I haven't put them in the ground yet because I am terrified of pests destroying them. Something, I think we've come to the conclusion it's birds, has taken every one of the 30 clary sage seedlings and 2 of my comfrey seedlings that I transplanted out. But why on earth would the marshmallow leaves now be turning PURPLE?! Gardening is supposed to relaxing

Also, when I first asked about the yellowing issue, the plants were all still inside, under the grow light. I was realllllly babying them and was nervous about beginning the hardening off process. I have since found out that plants do so much better if you get them outside as soon as they get their first or second set of true leaves. I started putting all of my younger seedlings out and it's incredible how they just take off! So I'm pretty sure that the yellowing was indeed a result of improper lighting. The peat pots have certainly become an issue since I moved them outside. There is absolutely no moisture control! They go from sopping wet to bone dry in a matter of hours. It's been a constant, round the clock battle everyday. Could that be causing the leaves to turn purple, the stress of constantly going from one extreme to the next???

They need to be in the ground asap. Rip off the peat pots and just get them planted. These are bone hardy plants that don't need fussing over.

Thank you so much for the help! I will get them in the ground today just as soon as it starts to cool down a bit. It's 90 degrees. Ripping off the peat pots won't hurt the roots?? Some have grown into it and through it

Soak them before removing the pots. You may break a few roots but it's better than leaving the pots on. As you have discovered they wick moisture away and will continue to do it even in the ground.

They are soaking as we speak. What fertilizer would you suggest for marshmallow plants? I've only put very diluted Alaska fish fertilizer 5-1-1 in the soil a few times and also used it as a foliar spray a few times. I want to grow the biggest, healthiest, most robust plants possible (probably everyone's goal in gardening lol). I am also growing licorice (glycyrrhiza glabra) from seed this year, for the first time, and can't find any information on the best fertilizer for them. Even though I've got them outside now, they aren't showing any progress. Do you happen to know anything about growing licorice?

I wouldn't fertilise them at all. They are tough wild perennials. All they need is sufficient moisture. In fact I have never fertilised any perennials. If they have reasonable soil and a dose of compost every so often they don't need it.

I've no idea about growing liquorice except that it is a robust field crop which can take hard winters. It is a tough perennial which needs no coddling.

Some plants will get purplish leaves when the cold hits them. Where I am, we are in the beginning of winter but you guys aren't so I don't know why the seedlings are going purple. I do think you are worrying too much, though.

Peat pots are one of those inventions that sound great, but aren't that good. As floral says, they dry out quickly. And despite what the instructions on the packet says, it is best to remove the peat pots before you plant out your plants.

Marshmallow is tough and probably hasn't enjoyed the fuss : ) Like 99% of plants, they want to be out in the sun and the rain.

Regarding fertilizing, I don't fertilize either. I do feed my soil as that is one of my hobbies. However, Seasol is a good product. It needs a lot of diluting. Only dilute the amount that you plan to use straight away.

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Peat pots encourage frequent watering because they dry out so quickly. That leaches out all the nutrients from the medium. Even plants with low or no fertilizer requirements in the ground will suffer if they grow in completely nutrientless medium in pots beyond the point at which their endosperm is depleted.

While I wouldn't normally fertilize many perennial herbs, a small, one-time "rescue" dose of high-nitrogen liquid fertilizer can help them recover faster and won't have long-lasting negative effects on the plant. But given that the newest leaves are green enough, I think just planting out will be fine. It even the new leaves are yellow and pale on some plants, I'd fertilize once.