Coming to grips with aphids on seedlings and plants (tips)

I have come to accept that aphids are a part of my gardening experience. 

I can do everything right; still, something will happen, and there they are, aphids and often in combination with white flies for some reason.

I have already published a YouTube video on detecting aphids on pepper plants. But this article will share my approach to tackling aphids and pests on seedlings and young plants.

I would not go as far as to call them hacks as I am sure they are not unique; still, together, they help me cope with aphid infestations.

7 tips for tackling an aphids infestation

First, let’s look at one of these aphids so you know what we are looking for.

Close up of an aphid
Close-up of a green aphid

This particular aphid was found on top of an overwintering sage plant. And unfortunately, there were plenty of them all over the plant. Still, I caught it early, and following the tips below, I am confident the plant will bounce back.

1. Watch out for shifts in temperature and dry-outs 

As in the example with the sage plant I mentioned above, I checked the plant as I noticed large temperature shifts during the day and night.

In four-season climates, early spring often brings nice and hot days with cold nights. This is when dry-outs happen, and this can cause plant stress.  

And as always, I found my first aphids on plants in that particular greenhouse within days.

As the weather gets hot during the day, the temperature builds up to summertime temperatures inside the greenhouse, even with open ventilation windows. The plants seem to get stressed by high daytime temperatures, followed by cool nights (below 10C / 50F).

So why not change my ways if this happens every year? I wish I could, but I do not have the resources to build temperature-controlled greenhouses. And when the weather is too cold to move the plants outdoors, I work with what I have.

2. Early detection and removal

Aphids will kill your plants if left unattended, but they are not dangerous or bad pests. They are more like an indication that something is not 100% right in your growing environment.

And if caught early, you can relatively easily eliminate them by daily inspections and manual removal.

It is time-consuming, but early detection is critical in beating any pest infestation – and definitely the fast-reproducing aphids.

3. Move infested plants to the side

If you find aphids on a plant, move it to the side and keep it isolated. 

Next, if you have the space, also move the plants that were in direct contact with the infested plant. 

When the plants are isolated, it is time to go aphids hunting. 

4. Check the morning after and then the next day

You located the plant, inspected it, and manually removed any signs of aphids. Great.

Now, repeat the manual inspection for at least 3-5 days until you have a minimum of 2 days with no aphids found. 

Aphids reproduce at an alarming rate, and you will not cure your plant in one go. Stay with it, and you will be victorious.

5. Remember to check the soil

Inspecting plants for aphids means moving branches and leaves to check every conceivable nook and cranny. And in doing so, you will cause some aphids to fall off the plant.

Depending on the type of aphids, you will see small creatures crawling in the pot, and trust me; they are always looking for a way to get back up that plant.

Aphid quick to climb back on plant after falling off
Aphids are quick to climb back up if given the chance

Carefully inspect the soil and remove the aphids when you find them. Looking closely and watching for movement can help if they are not bright green against the dark soil.

6. Why did your first leaves shrivel up and die?

First leaves, or cotyledons, are just that, the very first and generic-looking leaves that sprout from the germinating seed. Later, as the seedling develops, we see true leaves with the distinctive shape and pattern of our growing plant.

And we expect first leaves to shrivel and die when they have performed their duty.

But remember to check your first leaves, as they sometimes harbor aphids waiting to spring into action.

Aphids hiding underneath a wilted first leaf
Aphids underneath a wilted first leaf

7. Wash your hands between plants

Aphids are small and sometimes very difficult to spot with the human eye. Wash your hands after handling plants infested with aphids to avoid spreading aphids to your other plants. 

8. Check the soil, stem, and fresh new growth

When looking for aphids on a plant, I first check the soil, stem, and fresh new growth. And yes, this means gently opening up new young leaves to check inside. 

You can check each plant carefully if you have a couple of plants. But with many plants, checking these three locations helps me find aphids early.

Hold leaves up against the light and watch for dark spots. These dark spots can be tell-tale signs of aphids.

9. Ants on your plants? Take a closer look.

Ants love aphids and feed on the sweet honeydew aphids excrete. If you notice ants crawling around your plants, check for aphids.

Ants are not harmful in themselves, but the presence of ants should be seen as an indication that something may be off.

When all else fails, Neem oil to the rescue

Neem oil sprays are not as effective as some available commercial pesticides.

However, I have found that repeatedly treating plants with Neem oil and water solutions works.

Related: This is our recipe for our Neem oil water spray.

Yes, it does require more than one application. But I am willing to pay that price as Neem oil is organic and natural.

Treating plants using a manual spray bottle does get tiresome, but with the help of a manual pressure pump sprayer or a far-reaching garden pressure pump sprayer, the job gets a lot easier.

Apply the Neem oil solution in the morning or evening. Remember to water the Neem oil treated plant at the base should it need watering. 

Mattias Magnusson: Hello, I'm Mattias, a passionate and experienced gardening enthusiast. I am the creator of, your guide to year-round herb and veggie growing. Let's simplify green living, no matter your space or location.