When to clip extra plants?

[mvpstudio]

I'm a first time tomato grower from seed. I've started 3 varieties, 10 beefsteak, 10 San Marzano & 10 cherry. I used the 3" jiffy peat pots so I shouldn't have to repot at all until they go in the ground. All 30 pots have seedlings, most have 3 per pot as I was advised to put 3 seeds per cell. The secondary true-leaves have begun to emerge now on the 14th day. I'm not interested in repotting the extra plants, when (at what point) should I snip off the unwanted plants? Should I try to estimate which one of the 3 in each pot appears strongest? I'd love some advice. Every site I've checked says its ok to separate or snip but nobody says when to do it.

[GardenThrive]

I plant in cell trays doing 2 seeds for each cell. When the first true leaves have fully formed I keep the ones that are the biggest and most healthy and snip the others off even with the soil line. You could also separate the extras when you repot the seedling to have double the plants. I have done it both ways. The thing to remember is that when you have multiple plants in each cell, they will use more water and nutrients the longer they are allowed to grow, so ideally if you're not planning on keeping them it's best to clip them as soon as possible.

[mvpstudio]

The true leaves are still very small in comparison to the starter leaves, only 4-5 day since they sprouted. I suspect I should wait until they are around the same size? no? Do you ever water with miracle-gro treated water at this stage?

[GardenThrive]

It's fine to go ahead and clip them now. Just keep the ones that look the healthiest. If they look about the same just choose your favorite. After the true leave are fully formed is when I start fertilizing with a diluted mixture. From the look of the pictures you posted they were about a week away from being fully formed. I have used miracle grow in the past and diluted it to 1/3 strength. These days I go organic by using a liquid seaweed fertilizer.