Oh yeah...did that last year. My tomatoes and tomatillos were so huge by the time I was able to plant. They weren't fully hardened off...and it was just a mess. (I always start squash seed outdoors).

Can you cover them if you do plant outdoors? Have they been hardened off?

Last year, we had such crazy weather; warm and windy or cold with night freezes. Just couldn't get them hardened off and they were 2 ft. tall! What ended up happening is they were planted "trench" style. I put a large metal food container around the plant to help protect from the wind and offer some shade as they finished hardening off. And went between covering with shade cloth and frost cloth depending on the day's/night's weather. It wasn't my best year, but the plants did produce.

Good luck. Let us know how they do...and what you decide.

With your seedlings, how do you define massive? My idea of what I'd consider massive seedlings might be different from yours and vice versa.

I do not know anything about your level of gardening experience, so forgive me if I assume you don't have a lot of experience and start back at square one by mentioning info you need to consider.

There are several things to consider.

The plants you mentioned are warm-season plants and we still are in the cool-season. The plants you mentioned are tender (tomatoes and corn) and very tender (squash). In a minute, I'll explain what that means for them.

First of all, plants should be transplanted into the ground because it truly is the right time for them, and not merely because they were started too early and cannot survive indoors any longer. The right time for each specific type of vegetable means the soil temperatures are stable and are staying above the minimum needed by that specific type of vegetable.

Secondly, there's air temperatures to consider as well. If the air temperatures are too low and you go ahead and put plants in the ground too early, the plant growth likely will stall and the plants will become stunted due to the cold. When plants become cold-stunted, they often are slow to grow and produce poorly, if at all, even after soil and air temperatures have warmed up to what they like.

Third, if you do plant all these into the ground too early, you need a firm plan in place with the supplies on hand to protect them from cold. I have frost blanket type row cover in multiple weights (each weight gives a specific amount of cold protection and each one allows a specific percentage of sunlight to come through and reach the plants). The ones I use in March and April if I have warm-season plants in the ground and cold air temperatures return or a frost/freeze seem likely) are rated to give 8 degrees or 10 degrees of freeze protection. I use the 8-degree one if we are not expected to go too far below 32 degrees because it allows better light transmission, but I use the 10-degree ones if we are expected to drop into the low 20s or upper teens. They don't always prevent all damage, but they do prevent most of it. They are tricky to use in windy weather as they are lightweight and can get blown away very easily. If this happens at night while you're sleeping, you won't know it and you'll wake up to missing row cover material and frozen or freeze-damaged plants. I use multiple methods to hold the frost blankets in place on windy days/nights, and some of them require a lot of time in the garden. I have several thousand square feet of them and could, in theory, cover both my large garden plots with them, if needed, but I rarely go that far because the more you cover, the longer it takes....and it can take several hours to get all the row covers in place and properly weighted down so they won't fly away.

Fourth, if all the seedlings have been grown indoors with zero exposure to real sunlight and real wind, they will need to be hardened off to both sunshine and wind through gradually increasing their time outdoors. The standard method that has worked for gardeners for decades is to put the plants outdoors for 1 hour the first day, 2 hours the second day, 3 hours the third day, etc. until they have built up a tolerance for the long periods of sunlight and wind in which they'll be growing. If you take plants that have spent their whole life indoors and put them outside in the ground where they will be exposed to sunlight and wind for up to 12 hours a day right now, then they are likely to be damaged very badly wind wind and sun exposure and probably will die. They need to be hardened off properly before they go into the ground.

So, as I mentioned, with each vegetable type that we grow, there are minimum soil and temperatures they need in order to produce well. No matter where you are in OK, our soil and temperatures are not yet warm consistently enough for tomatoes, sweet corn or squash plants to be happy if planted in the ground now. It also is likely the last freeze and frosts have not occurred yet. If you're in southeastern OK, your odds of getting away with such early planting are a little higher than if you're anywhere else in the state. Even in the counties down here along the Red River in south-central OK, we are still waiting for soil temperatures to warm up a bit.

Soil temperatures matter in two ways. 1) They are important for good germination in a timely manner. Since you already germinated your seeds indoors, this really doesn't matter to you at this point. 2) Plants put into cold soil often just sit there and stare at you, making no effort to grow at all. This is because they cannot grow in cold soils, so nothing is gained by putting them into the ground too early because they cannot grow in cold soil/cold air temperatures. There's a reason all veggies are considered either cold hardy, semi-cold hardy, semi-hardy, tender or very tender and it has to do with the combination of soil temperatures and air temperatures needed by each type of vegetable plant in order for proper growth to occur.

To address each of your plants:

Sweet corn is tender and can go into the ground once soil temperatures have stabilized and are staying at or above 50 degrees consistently (including at night). I choose 5-7 days as a bench mark, meaning my soil temperature in the specific raised bed where I'm going to plant need to be at the correct soil temperatures for that long before I'll transplant anything into the ground. When you put corn plants into soil with temperatures below 50, they stunt and stall and just do not do well. And, with the 50 degrees, I'm talking about standard sweet corn. If you're growing supersweet corn, that soil temperature needs to be staying at or above 60 degrees.

This OK Mesonet map shows 3-day average soil temperatures at 4" below grade level right now. I go a step further and check the soil temperature in my own beds with a soil thermometer.

Three-Day Bare Soil Temps at 4" Below Grade Level

Tomato plants are tender and need a soil temperature of 50 at a minimum, and some experts say 60 degrees. I have found that as long as the air temperatures are nice as well and the nights are not getting too cold, the tomato plants do fine at 50 degree soil temperatures. If the nights still are dropping into the lower 40s or upper 30s, the plants don't grow much so there's no point in exposing them to those temperatures if you don't have to. If the air temperatures are below 55 degrees when tomato blossoms form, the blossoms usually drop without setting fruit.

Squash plants are very tender and need soil temperatures of at least 60 degrees for summer squash varieties and 70 degrees for winter squash and pumpkin varieties.

Just to be clear, all three of these veggies will freeze or suffer frost damage if planted in the ground and left unprotected when cold weather returns.

These are your plants and it is your choice to do as you wish with them, but if you think you're going to beat Mother Nature by putting these plants into colder soil conditions than they can tolerate, well......it isn't good to mess with Mother Nature.

I always push my tomato plants into the ground as early as I can based on soil and air temperatures and I don't have any tomato plants in the ground yet, and won't plant any until it gets warmer out there and stays warm. I am about as far south as you can go in this state and still be in OK and not in TX, and our high temperature at our house today was 76 but our soil temperatures are still pretty low thanks to the recent, persistent cold. Last year, my soil temperatures were about 15 degrees warmer on this same date as are this year, so of course, I'm remembering those warm soil temperatures and wishing I could plant as early this year as I did last year, but it isn't going to happen. Based on the 8-14 day forecast, it shouldn't happen even if my soil temperatures edged up into the 50s sooner than I expect they will. Sweet corn and squash go into the ground quite a bit later than my tomato plants most years because often, the weather takes quite a while longer to warm up enough for them. Have I ever pushed the limits and planted sweet corn and squash much earlier than I should? Of course I have, and it wasn't worth it. Either they stalled, or I had to cover them up most nights to keep them alive...not just happy and producing, but just to help them survive.

Good luck with whatever you decide to do. Personally, if I were in your shoes and if I were not in extreme SE OK, I would not put sweet corn, tomatoes or squash in the ground yet.

Dawn