'Counting On': Duggars Worry About Jana's Big Surprise in Exclusive Sneak Peek

Jana Duggar's family wants to show her just how much they appreciate what she does for them, but the best intentions may go awry when things take a turn for the worse. In PopCulture's exclusive preview of Tuesday's all-new episode of Counting On, the TLC family ushers the eldest Duggar daughter out of town so they can construct her a dream greenhouse as a surprise thank you.

"Because Jana has done so many things for our family over the years, we thought it would be amazing to surprise her with a greenhouse," sister Jessa tells the camera. Mom Michelle chimes in, "Jana has really been such an encouragement to all of us in the family, investing in each of our lives and just always encouraging family gatherings and get-togethers. I think it was just one of the ways that we felt like would be really special for her to show her how much we love and appreciate her was to build a greenhouse for her."

Keeping Jessa busy for the next few days, brother John David Duggar and his wife Abbie volunteer to take Jana on vacation to Knoxville, where they'll keep her distracted while the greenhouse construction takes place back home. Having a greenhouse will be the perfect present for the Duggar daughter, who has developed quite the green thumb over the years. "As she's gotten older, she's taken a big interest in gardening," John explains. "She has one of those picturesque magazine kind of gardens that she keeps us all fed with fresh fruits and vegetables."

With Jana gone, dad Jim Bob Duggar takes charge of putting the family to work assembling the greenhouse, but there's a long way to go from the glass pieces and metal beams that come in. "The greenhouse came in. I mean, it doesn't really look like a greenhouse to me," Jeremiah Duggar admits. "I'm afraid when we get done with it, it probably still won't look like a greenhouse."

Plans to pour the concrete slab for the greenhouse also go awry right off the bat, with the rain pushing back the essential step at least one day. Jessa says nervously, "There's a possibility that this thing won't be completed by the time she gets back. I mean, she could get back and it might just be the frame going up." She adds sarcastically, "Surprise! Look what we're doing for you?" Counting On airs Tuesdays at 9 p.m. ET on TLC. For more on the Duggars from PopCulture, click here.