Something might be in order to get the watering process a little more uniform for this long 125 ft row you mention. How are you watering them? Soaker hose, drip?

I'm not really into drip irrigation, but if you are using soaker hoses, but a 125 ft continuous length hooked together is too long, that is, if that is what you are doing.

Usually, with soaker hoses, 50 ft is about the max for an area, if stretched out straight. Preferably 25 ft if you really want the watering to be somewhat even.

I water anywhere from every 5-7 days at most (even in my hot climate), mulch very thickly, and train the plants early on to drive their roots deep by not overwatering or overfeeding them when they are young - important.

How much to water is a function of soil tilth, plant size (and fruit set), temperature, and rainfall, etc. But in general, water evenly and deeply, mulch well. Let the top few inches of soil dry out before watering.

It can also help to pick anything with a fair amount of blush before watering or a rain, in terms of keeping cracking to a minimum.

Thanks suze9. I will be stating my fourth garden. It is western colorado so soil has a lot of clay, soil conditions are getting better with added mulch over the years. Right now I can till it up to about 7 inches. I am on irrigation so I row irrigate.

cracking is from irregular watering,Im still trying to figure out what "irregular" means can someone help?

It is not "irregular watering", it's "irregular" (inconsistent) soil moisture levels - really wet soil followed by really dry soil, etc. You need to try to stabilize the soil moisture levels as much as possible.

If you are "on irrigation" I assume you mean you are using irrigation ditches, right? Then shorter rows is the best way to even out the irrigation. You have to time ditch flow from point A to point B to point C etc. and end your rows at the point where the ditch flow slows and narrows. Depending on the incline of the rows and the rate of flow (both can be somewhat adjusted) that could be as much as 50' or as little as 10'.

8 hours is a long irrigation time. So I am guessing that either your flow rate is quite low - even more reason for far shorter rows - or your plants are getting way too much water. Over-watering causes far more problems than under-watering and most of us tend to OVER-water tomato plants anyway. So consider cutting back on both the amount and frequency of irrigation - the plants will adjust.

Mulch - It also helps a great deal to use heavy amounts of straw/hay mulch - 6" or so - to help retain soil moisture - especially at the ends of the rows that don't get as much water to begin with. Good mulching can resolve most all soil moisture problems and has the added benefit of improving the soil over time as the mulch decomposes. ;)

Should certain varieties be last to get water?

No, most all varieties need the same amount of water - approx. 1 to 2" a week depending on soil tilth, air temps, and humidity - and ALL need consistent soil moisture levels. Some varieties are more prone to cracking but all will crack if exposed to radical changes in soil moisture levels.

Good luck with your addiction!

Dave