Quick reminder: The water does not get turned on until the last frost date which in our area can be as late a April!
Here are some examples of ways to extend your season in Spring and in the Fall:
High tunnels are essentially small green houses, they are called high tunnels because there is usually a door that one can walk into and most of the time you can stand up in a high tunnel. I would love to have a mini greenhouse like this but am going to shelve that plan for when I have a large enough space in my backyard for it.
Low tunnels are perfect for p-patch gardening. They are called low tunnels because usually one cannot walk under them. They can be installed into garden beds or straight into the ground. The supports you use for your low tunnel can vary, PVC pipes are used as well as electrical conduit (this has to be bent with a conduit bender before use) or you can purchase lightweight metal supports to hold up your covering(s). Low tunnels are easy to disassemble as the weather warms up.
Plastic film (the thicker the better) and garden fabric can both be used as covers. Both have advantages and disadvantages: on super sunny days the plastic film may get too hot and your plants inside may burn, on rainy days they will keep the rain off but then you will have to water your plants inside, which may involve rolling up one side of the low tunnel to access the plants. The garden fabric is more breathable, it allows air and rain to your plants but it is a fabric and tends to rip more easily than they heavy duty plastic film. Both methods are great to retaining heat but also for excluding outside pest, they both however INCLUDE inside pests like slugs and snails. Be sure to bait for slugs or pick them off in the cool of the evening.
Cold frames are a wonderful place to start seeds and overwinter plants. They are usually made from wood and glass or wood and plastic sheeting. There are many cold frames plans on the internet available. Oftentimes cold frames are heavy because they are mostly made of wood, find a good study place to keep them and they will protect your plants for many seasons to come. Small and lightweight cold frames are available for sale but they are often flimsy, you will have to try them out and decide if they are worth the assembly time and cost.
Keep in mind that a cold frame is smaller in area than many low tunnels and it can get very hot in there. It is suggested that you install and automatic vent opener that opens the top pf the cold frame on a particularly warm day. See photo below, this vent opener will save your seedlings and plants from really baking in the sun.
Cloche is French for 'hat', In the garden, cloches are anything that protect your plants and gives them extra warmth. One can use glass cloches, upturned liter bottles, milk cartons and 5 gallon water containers. Remember to drill ventilation holes and secure lightweight plastic cloches or they may blow away in the wind.
I use 5 gallon water container and I think it is a great way to recycle. Beware that it will get hot in there, Watch your plants carefully to see if it might be getting too warm under the cloche. As you prepare to take the cloche off, make sure you harden off the plants that have been protected underneath. Gradually, expose them to full sun, wind and nighttime temperatures for 7-10 days before you completely take the cloche off and leave them to fend for themselves.
There are many, many, other season extending products on the market, It is a great idea to walk around the garden, chat with your neighbors and get their opinions of what works for them and might be convenient for you.