I have flower beds close to the house partway under the eaves.

If your plants are small you can cover them with ice cream buckets or 5 gallon pails. I have used tomato cages around smaller plants and then covered the cage with old sheets. You can also rig up a line of tomato cages and stretch the sheets over the top--use clothespins to secure. I have also used the leaf bins that you can collapse for storage--some are large enough to cover bigger plants. You basically want to keep the plants from getting frost on them in the 24 degree cold--it's the frost that kills the plant--not the cold--OR--depends on the plants--some tolerate cold much better than others. Keep the plants covered until it warms up to above freezing. I would not go so far as to add the fan.

COVER THEM OVER NIGHT. I USE OLD TOWELS UNDERSHIRTS. REMOVE AS SOON AS POSSIBLE

You will have to protect therefrom those temps.Use anything light weight to protect them .Do not use a fan that will keep them cold

USE NEWSPAPER TAPE TOGETHER IF NEED BE - NEWSPAPER GOOD INSULATION - ALSO IF ADD TINFOIL ON OUTER SIDE - MORE INSULATION

This is a less than ideal position as your weeping tile around the house is draining the rain away. Most plants will tolerate a light f4ost in the fall as they have aclimitized to the cooling days.

However in spring that temperature can shock the plants into stalling their growth. Protect them with lightweight row cover until it warms up

Do not use plastic, the cold will cause the plastic to harm it if it is touching it, and I found it doesn't really insulate as well as fabric does. I keep old bed linens to cover tender plants in the spring and fall. If you do use plastic, put fabric under it. You have to cover to the ground when you use cages and make sure you anchor in case the winds come up no matter what you use.

TY!