How do I care for my plants in the winter?

It's best to get information on this for your local area. Perhaps ask a local nursery or Google the information for your area.

If you live in an area that gets cold, hopefully you have them in pots and have already brought them in gradually. Sometimes bringing them in causes them to lose leaves, my hibiscus plants drop leaves no matter how carefully I get them ready to be brought in, but they begin getting new leaves immediately. If the leafless branches dry out and get brittle, they are gone. They do go dormant for a while when they are first brought into the house because of the change in environment. You may also need to provide additional light with a grow light to give them the light they need. Watering is a little different than outside because they don't have the higher humidity anymore, so they may need a little more frequent watering. Check with a local greenhouse for more specific information about over wintering plants in your area. Good luck with your plants! It will get easier as you get more into gardening, whether in ground or pots, or both and houseplants. Once you are more comfortable, start expanding you plants and in no time you will have a green thumb!

Everyone was a newbie at one point in time. Do you know what zone you are in? Find out here:

https://planthardiness.ars.usda.gov/PHZMWeb/

For lemons you have a few years to go.

https://www.gardeningknowhow.com/edible/fruits/lemons/propagating-lemon-seeds.htm

https://m.wikihow.com/Plant-a-Lemon-Seed

Here is one of mine. The photo on the left was on January 23rd. I transplanted it. The photo on the right was taken September 13th and has grown since then.

I am in zone 9 and they are out year round. I wrap when we have high winds.

Let me find you Dahlia info. They won't grow for me, too dry and hot here, but we grow them at my girlfriends house. Stunning flowers.

Here is some Dahl is info:

https://www.longfield-gardens.com/article/How-to-Overwinter-Dahlias

Dahlias are dug up after first hard frost, surface dirt knocked off, then placed in peat moss, over winter in a container. Store in unheated, attached garage. Water sparingly when first stored, then again in early spring. Do not return to outside ground until ground temps are over 50 degrees. Best to wait until after last frost for best success (late May, ezrly June in zone 6).

Lemon trees from seed can be brought indoors, given sufficient light and intermittent feedings throughout winter. Return outdoors at same time as Dahlias.