Have you ever thought you liked a terrible song just because you remembered it, mistaking mere recollection for actual nostalgia? That’s the way it is for me and “H. R. Pufnstuf.” I thought I had fond memories of the show until I had a chance to see it again, to hear the shrieks of an angry Witchie-Poo (the actress Billie Hayes in a ketchup-red wig), to be assaulted by swirling Day-Glo colors and a Freudian plot featuring a talking flute. Turns out that when I was 7, I had really, really bad taste.

Then again, maybe that’s the glory of being 7 years old: there are no clichés, and the crassest riddles rock your world. The brighter the colors, the better the set design. This was the evil genius of Sid and Marty Krofft — the Canadian-born 70’s TV hucksters whose invariably short-lived Saturday morning series included “H. R. Pufnstuf,” “The Bugaloos,” “Electra Woman and Dyna Girl,” “Sigmund and the Sea Monsters,” “Land of the Lost” and the deeply strange “Lidsville.” They weren’t making shows that parents could watch with their kids. They were making shows that kids could watch alone, while severely addled by Cap’n Crunch. In another league entirely from the witty Muppetry of “Sesame Street” or the gentle pleasures of Mr. Rogers and “The Magic Garden,” the Kroffts dished up a swirl of psychedelia, vaudeville and cheesy production values that might be described as brown acid for the toddler soul.

A marathon of the Krofft series runs this Tuesday, from 8 to 11:30 p.m. on TV Land, culminating in a variety show featuring the Brady Bunch performing “Proud Mary.” And if the marathon won’t win any awards for educational value, it reaffirms that the Kroffts were to children’s television what Joe Eszterhas is to the erotic thriller: schlock auteurs with a vision. To an adult, the Krofft jokes might seem fairly idiotic, like an endless comic routine featuring an owl asking, “Who?” (Or foolishly offensive, like an Indian tree saying, “They not call me redwood for nothing!”) The plots made little sense, and just when things seemed to have reached their lowest ebb, a character would burst out into a song like “Oranges Poranges.”

But there was some sort of guiding Krofft aesthetic — a bonk-on-the-nose entertainment value. Most often, there was a grossly cute monster, created by propping a puppet head on an actor: H. R. Pufnstuf; the one-toothed, googly-eyed Sigmund; or Chaka in “Land of the Lost.” There was a crushinducing child hero, like Johnny Whitaker in “Sigmund,” Jack Wilde in “Pufnstuf” or the adorable Kathy Coleman of “Land of the Lost.” There was a scary shrieking villain — frequently a Phyllis Diller-like mean old lady vamping around and stomping her feet. Most Krofft shows centered on an alternate universe like Lidsville, Living Island, Tranquility Forest or the prehistoric wormhole in “Land of the Lost.”

That people left their children alone with these shows is either a shameful indictment of our culture or encouraging evidence of the resilience of young brains. From an adult perspective, “H. R. Pufnstuf” is the weakest of the bunch, if only because Pufnstuf himself is so hard to look at, with his big pumpkin head and creepy giggle. “The Bugaloos” is a lot more fun, a fantasy of a super-groovy British pop band consisting of four low-key bugs: Joy, Harmony, Compassion and IQ. The winged Bugaloos live in Tranquility Forest (“the last of the British colonies”), singing their truly addictive theme song and battling their nemesis, Benita Bizarre (Martha Raye).

“Sigmund and the Sea Monsters” had a similar laid-back appeal, with its mellow seaside surfer ambience. “Electra Woman and Dyna Girl” was a cheesy Batman rip-off with a feminist undercurrent. And “Lidsville” gets points for sheer insanity, set as it was in an alternate universe inhabited by talking hats — a typical conceit for these shows, which were filled with imagery that would be right at home in 60’s drug comic books.

The best of the Krofft series is probably “Land of the Lost,” which had insanely bad special effects but a premise with genuine fantasy appeal. A family of three (the mop-topped forest ranger dad, Marshall, his tight-trousered son Will and the young Holly, with her blond braids, overbite and excessive spunk) are white-water rafting on “a routine expedition” when they’re pulled into a whirlpool — a vortex into another dimension, one in which Claymation dinosaurs roam the earth. They are forced to build a new life, with only their homesteading skills and the companionship of the Wookie-like Chaka. The villains are Sleestaks: hissing lizard monsters who lurk in caves, fondling magical glowing crystals. As a child, I found this show terrifically exciting, despite its slow pace — and frightening as well.

It would be nice to say that the Krofft productions had a rough and anarchic genius, that they were punk rock to “Sesame Street’s” Beatles. But the truth is, they were more like “Beatlemania.” Long before “Teletubbies” and “Boobah,” the Kroffts were happily demonstrating the very thin line between a child’s innocent imagination and the deepest neurological damage.