Without giving your zone and/or general location, photos, or a description of the problem and growing environment there is no way for us to know.

Rodney

Totally agree with Rodney about additional information. It is also highly recommended you put your location/zone in your profile so we are not guessing all the time at your location. Spraying plants with any chemical without knowing what the problem is may do more harm than good. The kind folks on here want to help each other so post away. Glad you are here!

Just a short word on the pesticides... it's really never good practice to use an insect killer without knowing what insect is causing the problem. In this case, it sounds like you sprayed it because you weren't sure what was causing your plant issues. Perhaps you did have an infestation of some sort, but if you can't identify the pest, snap a pic and post it here. We can often help quickly identify a pest, and offer advice how to treat them properly and effectively.

Edit: dirtguy50's post wasn't showing when I commented... what he said.

Posting a photo of what "looking poorly" means would really help. Plus we need much more info to be of any assistance.

For future reference, unless you see the bugs/pests and see them doing actual damage and then first identify the pest, you never spray a pesticide on the plants. They can, as dirtguy said, do more harm than anything else.

There are many other possible causes, more likely causes, for things doing poorly than pests. The condition and nutrient levels of your soil is the first thing to consider. Using the proper planting time is the next. Hardening off any transplants before planting them in the sunny garden is another.

So please get back to us with much more information including your location.

Dave

Why would you want to spray anything on what you will eat yourself?

One of the biggest reasons (for me) to home garden is so I know what is getting sprayed on my food. In my garden it's nothing. Believe it or not using a broad spectrum insecticide kills even the good bugs.

Yes, there are good bugs too, esp. the pollinators. But killing them off throws things out of balance cuz the bad bugs will come back with a fury. So give it time after you stop using insecticides for things to get back in balance. Google for natural enemies.

There are things like manual removal of squash bugs and their eggs using tape while it will consume more time but are very effective. Be sure to check the underside of leaves on plants you are having problems with.

Hmm I had hoped we'd hear back from the OP by now with more info.

Don't spray for insects until you see insects. (Well, I'd say don't spray even then, but that's a different debate.)

You don't say what "poorly" means. If they're not damaged or showing obvious disease, but seem to be halfhearted about growing, possibilities include:

- Rootbound seedlings for which you haven't loosened the root ball. (It's better not to have rootbound seedlings anyway, but if the only instance of that tomato that you really want is rootbound, you may buy it anyway. If so, you have to do some work on the roots.)

- Underwatering. Often people will sprinkle until the surface is shiny, but there's a dry layer just below. Dig a hole or stick a finger in there. You want to water deeply, which can take a long time, but not too frequently.

- Overwatering. Again, you don't want to water too frequently. The soil should be pleasantly moist, like a moist cake. It shouldn't be dry and it shouldn't be sopping for long after watering.

- Bad soil plus lack of soil prep. You don't need gorgeous plush soil, but if you just hacked a mug-sized hole out of bad soil, the plant may treat that hole like a "pot" and not expand out from it.

- A severe lack of fertility. I say "severe" because I've often grown tomatoes in fairly bad soil that was probably low in fertility, without adding a bit of fertilizer, and they've been fine, as long as I dug decent holes, corrected rootbound root balls, and so on.

- Shade. It's easy to fool yourself into thinking that plants will grow with a lot less sun than they really will.

- Temperature. If you planted heat-loving plants like tomatoes and squash too early, they may survive, but not thrive.