It's fine. What you have is an all purpose fertilizer that can be used during both stages (veg and flower). The fact that is says "tomatoes" is just marketing. Its like with CD-Rs, some say Music CD-Rs and others say Data CD-Rs, when they are the exact same thing.
When looking at fertilizers you want to read the NPK on the back. In this case it's 4-5-8. The numbers are ratios or put another way, percents by weight. What confuses most people is when they see one bag with NPK of 4-5-8 and another bag with NPK of 12-15-28. You might think the higher number is better, but it's not. Since it's a ratio, it's actually the same, the latter is just more concentrated so you'll need to be extra safe by using less of it. Personally, I prefer small numbers over high numbers. I like to error on the side of less nutrients so I don't burn my plants, but that's purely personal choice.
Now understand that during veg, the plant is going to need a lot of N, but only a tiny tiny amount of P & K. Having it in the soil is fine, the plant just won't take advantage of it. When your plant starts to flower, the opposite holds true. Your plant will use a tiny tiny bit of N, but a lot of N & K. Knowing this, some growers (myself included) will use two separate fertilizers. One that has little or no P&K for veg, and one with little or no N during flower.
I haven't seen any good side by side tests that show me one method is better than the other and since you've already invested in this brand, I say give it a chance and go ahead and use it as it's recommended.
Hope that helps. Happy growing.
- Vin
