Ask This Old House S25E3: PEX Hose Spigot, Cover Crops, and Richard's Cutaway Habit

Season 25, episode 3 of Ask This Old House splits its time between two things that have almost nothing in common on paper: a backyard hose spigot run on PEX, and a pair of cover-crop lessons, one at a 500-acre Rhode Island farm and one in a homeowner's raised beds. What ties them together is the episode's opening act, a look back at the cutaway, the show's habit of sawing a fixture in half so you can see the part that fails. Plumbing and soil both hide their important work. The cutaway reel just makes the case out loud.

The cutaway reel, and why it still works

Kevin O'Connor and Richard Trethewey spend the first few minutes trading memories of sliced-open objects: a dishwasher from the first season, toilets, air vents, a water heater, Mauro Henrique's paintbrush. The format should be gimmicky and isn't, for one reason Richard names directly. When a homeowner sees the inside of something they have used their whole life, the light bulb goes off and the understanding sticks.

The two best examples in the reel are also the two most useful. Mauro's paintbrush cutaway shows why you shouldn't leave a brush sitting in a can of solvent: paint and water get forced up under the ferrule, the metal band that holds the bristles, and the bristles rot from the inside. Richard's toilet cutaway points at the spot where a stoppage usually happens, the passageway inside the bowl that narrows down before it exits. Neither fact is obvious from the outside, which is the whole argument for the cutaway.

Tom Silva's contribution is the water heater autopsy, where the same tank that holds potable water comes open to reveal rust. Richard's answer in the transcript is a cheerful "with a little bit of rust." I have watched enough of these to know that the rust is not a little bit, and that the segment exists to make you think about the age of your own tank.

This is the same instinct behind Richard's toilet tank anatomy lesson in S24E20, where he walked Kevin through 150 years of tank parts to explain a running toilet. Same trick, different fixture. Show the mechanism, and the repair stops being mysterious.

A backyard spigot that doesn't freeze off the wall

Homeowner Nick bought his house about four years ago, has a baby on the way, and has exactly one hose spigot, in the front yard. Richard picks a spot through the deck sill near existing hot and cold piping, so the new line can tie into a supply that's already there.

Before drilling anything, Richard runs through the choice of fixture using cutaways of the fixtures themselves. A conventional garden faucet has its washer and shutoff outside the house, which means full city water pressure sits against a part that is exposed to winter. If that freezes, it can split off the side of the house. The alternative he pulls out is a frost-proof sillcock. It looks nearly identical from the yard, but the shutoff point sits far back inside the wall, close to the conditioned space, so standing water isn't trapped out in the cold. On an old house where the rim joist area already runs cold, that difference is the whole ballgame.

The exterior work is quick on screen and less quick in reality. Nick drills through the sill, Richard has him seal the penetration with silicone so the flange makes a tight water seal against the siding, and the fixture gets mounted. The transcript skips over the parts you'd hit at home: figuring out where the rim joist actually is, avoiding the wiring that may run through the same bay, and getting the exterior hole pitched so water drains out rather than in. If you're planning this, that locating step is most of the job.

Crimp, pinch, or expansion: picking a PEX connection

Richard's stated reason for going PEX instead of copper is honest: this is more of a do-it-yourself project than sweating pipe would be. Then he lays out the menu the way a home center aisle presents it, with the cutaway versions in hand.

• Push-to-connect fittings. O-rings and stainless barbs; you push the pipe in and it clicks. No proprietary tool, which is the selling point. Richard priced the full job in copper with these fittings at over $200 in parts.
• PEX-B with a crimp ring or stainless crimp sleeve. A tool crimps the ring over the pipe. The stainless sleeve has a witness mark so you can confirm the pipe is fully inserted, which Richard says he likes. Roughly $120 for fittings plus tool.
• Pinch connection. A stainless sleeve that a different tool ratchets down tight.
• PEX-A expansion. The expander stretches the sleeve and the pipe, and the material's memory pulls the joint tight. Richard's preferred method, about $150 with the tool, which came in under the copper route.

Nick picks PEX-A. To tie into the existing copper, they use a copper-to-PEX tee with push-to-connect ends, which is a sensible way to bridge the two materials without a torch.

The details that matter are small and easy to skip. Nick cleans the copper with emery cloth before cutting, so the O-rings seat against a clean surface. He marks both sides of the cut, then uses a small tubing cutter, the kind made for tight spaces, and Richard warns that the first revolution is the hard one because the wheel has to track back into its own groove. The transcript also notes why not to grab a hacksaw: it leaves a burred edge, and burrs and O-rings don't get along. On the PEX side, the expansion tool gets cycled and the fitting pushed on after each pass, all the way in, before the material closes back down.

Here's the line that keeps this segment honest. Richard says, as they're working, "It's not completely do-it-yourself," and both of them laugh. He's right. You still have to shut off the water, cut into a live copper line, and hold pressure afterward. The tool is proprietary and the failure mode is a leak inside a wall. Knowing which connection to buy is the easy half.

What a 500-acre farm knows about cover crops

Jenn Nawada visits a Rhode Island farm to get the farm-scale version of an answer before she gives the garden-scale one. Farm manager John defines a cover crop as a sacrificial crop, grown to hold soil against wind and water erosion rather than to be harvested. The one in front of them is winter rye, which he calls a scavenger: deep roots pull nutrients up, and soil microorganisms then feed on the crop and mineralize it into a form the next planting can use. In his framing, the cover crop is fertilizer that grows itself.

Timing is the part growers guard closely. The rye they're standing in has headed out, with seed forming but not yet mature. Once it matures and drops, it reseeds itself, and that's too late to terminate it without creating a weed problem. Jenn asks the question a homeowner would ask, which is when to do this at home, and the answer is the same shape as the farm's: seed it when the garden is finished for the year, and deal with it in spring before it goes to seed.

Oats, winter peas, and hairy vetch in raised beds

Homeowner Amy's garden started as two beds in the back and has expanded. At the end of the season it looks rough, and Jenn's point is that rough is normal; the problem is bare soil sitting through winter, where rain, wind, and freeze-thaw wash it away. Cover crops stabilize the surface, improve water infiltration, and suppress weeds.

Amy raises a real constraint: her daughter has celiac disease, so wheat, barley, and rye are out. Jenn swaps in oats, which grow, winter-kill, and leave a carbon-rich mat that's easy to turn over in spring. To that she adds winter peas and hairy vetch, both legumes that fix nitrogen. The seeding itself is deliberately low-tech. Clear the spent vegetables and flowers, rake and turn the soil, broadcast the seed by hand, feather it in, cover it lightly, water once. Jenn gives a rate of roughly 600 square feet per pound of seed.

She also gives Amy a calendar anchor rather than a date: take the usual mid-May planting time and work backward two to four weeks for terminating the cover crop. That's the kind of instruction that survives contact with an actual spring.

Jenn's habit of coming back to see what happened is the through-line in her segments this season. In S25E1 she revisited a garden she'd helped transform a decade earlier. Here the return trip is a season, not a decade, but the question is the same one: did the soil respond?

Spring follow-up: clip, mulch, and watch the vetch

Jenn comes back months later and the first thing she checks is erosion. The soil stayed put, which was the point. She and Amy clip the cover crop at the base and pile it to use as nitrogen-rich mulch, and Jenn says the material can be left to break down for about two weeks with a little water before planting.

Amy admits she turned one bed's cover crop in rather than clipping it, because she wanted to start onions and potatoes there. Jenn doesn't scold her. She calls it trial and error and tells her to compare the crops and the flavor against other beds.

The one genuine caution is hairy vetch. If it flowers and goes to seed, it will scatter through the bed, so Jenn says to pull volunteers as they show up. The broader message is that cover cropping is a practice you tune by keeping notes, which is exactly what Jenn tells Amy to do.

DIY Confidence Scale

Adding a hose spigot on PEX: 5/10. The fittings themselves are forgiving and the tool does most of the thinking. The score drops because you're cutting into a pressurized copper line, drilling through a rim joist you haven't seen yet, and living with the result inside a wall. If you've never soldered or crimped anything, this is a good job to watch done once before trying.

Planting a cover crop: 2/10. Seed, rake, water, wait. The only real skill is reading the calendar and knowing when to terminate before the crop reseeds.

Additional Resources

• Watch on PBS
• Official This Old House episode page

Richard's best argument for the cutaway wasn't nostalgia, it was that people use a fixture their whole lives without knowing what's inside it. Which raises a practical question for anyone with one hose spigot on the wrong side of the house: would you rather see the inside of your rim joist before you drill, or after?