sujiwan

Is it possible to plant them out close to dusk? If it's going to rain, that will be a plus if they have 8 or 9 hours of darkness to recuperate.

I assume you know, but you must harden the plants off first if you haven't yet. If you want to get them in the ground immediately, can you cover them with something for a week for shade to harden them off? You don't want them to scald and die after the trouble of raising them from seed.

If they're already hardened off, ignore that last part!

I think my question is more of a general one about transplanting warm weather plants when the days temps are somewhat high. How harmful is it if you don't have the ideal time available and how can one mitigate the problems in that case?

In my circumstance there are factors that involve the reliability of another person "getting around to planting" in my stead versus me just getting the job done while I am available there to do it --which is unfortunately not at dusk or early morning. SIgh.

The best way to do it is to make sure the rootball is soaking wet and then wet down the ground well. Water loss is the killer in heat because roots get damaged during transplant and/or are not connected with the surrounding soil so they have little soil to pull water from. Soaking the ground will increase humidity and thus decrease water loss from the leaves a little. that should get the plants through the day. If you are doing something like Tomatoes and can pinch off a big lower leaf or two that will help. Less leaves mean less water loss. But in doing so you also slow down growth a bit.

You would also want to make sure the soil does not dry out for a few days.

sujiwan

Yes, I understand about wanting to transplant them yourself and not rely on somebody else.

As long as your hot-weather plants are hardened off, any of them, you can plant them when temps are high. They will be a little sulky from being transplanted in high temps but should be fine in a couple of days. But just don't give up the steps of hardening them off.

As long as you're not having to pull apart the root ball, the advantages of being in the ground vs stuck in a pot outweighs any passing discomfort...IMHO..

Just a thought, if there is direct sun when you transplant, can you shade the plants with a makeshift awning of sorts?

Ditto's to Anney's suggestion of covering the plants for a few days after transplanting. An upsidedown plant/shrub pot works great. This is one of the first things that I learned from my grandfather "many" years ago. This allows the plants to develop a root system before being exposed to heat and sunshine. For me, usually 2 to 3 days has been adequate.

I planted out tomato and peppers during 90 degree weather before. They were properly hardened off and had no ill effects whatsoever. I would recommend watering it daily afterwards if there is no rain.

Do it in the evening, on a day it is rainy or on a day it is cloudy. I wouldn't do it in full sunshine on a 90F day..i'd at least wait until near dark conditions and then water. I just planted 6 trees during our heat wave here and they are doing fine, i just did it in the evening. I once moved 7 good size arbor vitae in late June during an all day rainstorm. That was 2 years ago and they've grown way more then they ever had.

franktank

He says he can't do it at dusk. I recommended it. So I think probably Grandad's suggestion of planting them and then covering them with something like a clay pot or even an upside down laundry basket with open weave on the sides would be best if he has to set them out at mid-day.

Ditto to instar 8.....get them in the ground. I transplanted 21 small plants this afternoon [85°] and thought nothing of it when the root ball is intact...no swhade needed for most plants.

I think this question is about terms.
As I understand them, "transplanting" is digging a plant up from somewhere and re-planting it somewhere else. This is not wise to do on a ninety degree day,since you are disturbing the roots considerably. This process will go better if you do it at night, and even better if it's done right before rain. The plant should be watered thoroughly the day before you dig and immediately after it is set into the ground. You need to pay attention to its moisture needs for a couple of weeks.

"Setting out" is turning a pot-grown plant out of its pot, without disturbing the roots, and setting it into place in a garden bed. As long as you water the plant well before you turn it out of its pot (a couple hours before is even better so the plant is fully hydrated), and you water it well after it's set into the ground, the plant will do perfectly fine and should suffer no problems whatsoever.

Another makeshift awning I've used is to set 1-foot stakes in the ground around the plant, and use a clothespin to attach a square of fabric (like a piece of old bedsheet) over the top. This worked very well also, with row cover rather than a bedsheet, for setting out plants that I hadn't had time to properly harden off.

I hope so, I am moving my tomatoes to the back yard this week and putting them under shade cloth to help with the heat!! I want to extend the season as much as possible!! I am taking them from 5 gal buckets and putting them into the big 35 gal earthtainers! I hope they survive!!