I assume the clover seed you're planning to add is Dutch White clover. DWC used to be added to most seed mixes, but when broadleaf weed killers started gaining in usage, clover was seen as a weed and its use in lawn seed mixes fell.

I seeded strawberry clover in my lawn (similar to DWC, but better adapted to alkaline soils).

I think DWC spreads via stolons, rhizomes and seeds. PR is essentially a bunch grass, although it tillers (new shoots next to the existing plant).

Unless you overseed periodically, the clover will likely become a steadily larger proportion of the lawn. Whether that's a bad thing is for you to decide.

Why does it have to be all perennial rye? A nice perennial rye lawn looks great, but you will have to overseed periodically unless you use some of the newer spreading PR's, and those are so new that there isn't a lot of data on how it performs over time. Perennial rye can also have a lot more disease pressure than some grasses, especially if you live in a humid area. I would forget about the clover unless you like how it looks. The nitrogen fixing doesn't mean you won't have to fertilize, and if you are anti-fertilizer you can always go organic.

THANKS for the comments. They are helpful.

I'm considering the clover OR something else because my yard is a VERY HEAVY CLAY. When I seeded it with Perennial Rye before...it did well....but I had some problems with my well so I wasn't able to keep it well-watered and it perished before I got my water-problems solved.

I chose the rye grass because I LIKE the fine narrow leaves rather than the large coarse leaves of some grasses. THOSE I truly dislike! Our area is very arid...not at all humid.
Ryegrass also stays green much better and longer in this area.

I don't mind "over-seeding" some areas in the future...although it would be NICE if the ryegrass was a "spreader".....I will have to look around a bit on the internet to see IF I can find seed for a "spreading ryegrass". I wasn't aware that such existed.

I do have a COMPOST pile that I will spread over the area prior to tilling and re-seeding. It should be a fine compost since I also raise chickens and incorporate the droppings into the other compost materials. (I don't expect to NEED "fertilizer". I'll just spread my compost occasionally -lightly). I expect that to "do-the-trick" as far as fertilizer and soil improvement is concerned. Especially IF I run an "Aerator" over the lawn each year or so before I spread more compost.

Maybe instead of CLOVER....I should just put a zillion worms out in the lawn to break-up this hard-pan Alkali Clay!
Ha-Ha !!!

THANKS for the advice. ANY further suggestions are certainly WELCOME and MUCH APPRECIATED!!!
-Junkmanme-

Your location is a little tough to read. Is it northern New Mexico?

Where exactly (zip code is good enough)? If it's NM, what elevation?

Yes, It is Northern New Mexico, near Gallup at 6500 feet elevation. We are listed as Zone 5, but in reality it is much colder and I would equate the gardening zone more with Zone 4 because of our weather here. We were 27 BELOW ZERO about a week ago. ( Although somewhat unusual...not at all rare here.)
-Junkmanme-

I would think that Kentucky bluegrass would be a better fit for you than perennial rye. It meets your desire for thin blades, and will also fill in bare spots. It will go dormant if it doesn't get enough water, but will come back after a relatively long dormancy.

Since your soil is alkaline, you might want to go with strawberry clover rather than Dutch White clover. DWC does better in acidic soils and strawberry clover is better suited to alkaline conditions. The best strawberry clover for drought conditions is Palestine. Mine stayed green last year even though I only watered three times.

If you're trying to get a lawn that will do well with minimal input, you might want to consider using native grasses and/or naturalized grasses. Streambank wheatgrass and sheep fescue are both native. Crested wheatgrass is an import from Siberia, but it does well with little water. All three of these have fine blades.

Sheep fescue is a bunch grass. It requires the least amount of water of the three, but it doesn't do well in heat. It goes dormant when it's hot but snaps back when it cools down.

Streambank wheatgrass would probably need a little water to stay green all summer, but if it goes dormant, it can stay dormant for months and snap back. If you water once a month or once every 6 weeks, it would probably stay green. It also spreads via rhizomes.

Crested wheatgrass will stay green with about the same amount of water as streambank wheatgrass, but it goes dormant a bit faster. It's mostly a bunch grass, but some newer varieties will spread a little via rhizomes.

bpgreen,

THANKS again for the input!

Kentucky Bluegrass is certainly a reasonable alternative to Perennial ryegrass! I have considered that and may possibly mix a little bit of Bluegrass seed in with the ryegrass. I'm sure that ...over time...the Bluegrass would crowd-out the ryegrass....but probably NOT in MY remaining Lifetime.

IF I put clover in...I will be SURE to look favorably upon the Strawberry Clover....particularly "Palestine".

I've even thought about perhaps putting some Alfalfa seed in the mix because it has GREAT ROOTS....to help break-up this hard-pan soil. But it probably wouldn't do well with me cutting it all the time.

The chickens I've got in the SIDE-yard would no doubt like the clover or the alfalfa when I let them into the front yard occasionally.

I'm not concerned MUCH about "drought conditions". My well is DEEP and there is plenty of water....(an underground river flows here). The Bluegrass will probably use about the same amount of water as the ryegrass. The lawn is fairly small....about 1200 sq. ft.

I might toss some Strawberry Clover seed around in other spots of my yard just to help this muddy (NOW) soil become a bit more stable.

I'm going to "look-around" for a source of "spreading perennial ryegrass", also.

I much appreciate your "hints" and the benefit of your experience!
THANKS !!!
-Junkmanme-

I agree with BP but I think we are overlooking something. Your soil. Obviously you can't change you soil composition drastically or overnight, but it sounds like you could benefit from frequent applications of organic matter. Also you can do a simple soil composition test on your own to be sure if your soil is in fact mostly clay. I wouldn' be a bad idea to have a soil lab test your soil too if you are going to start a lawn.