What to do if they're nice in person but barely text

A short reply from someone who was warm in person usually means texting is low effort for her, not that she lost interest. Some people only text to set up plans, so a message with no question gives her nothing to do. Look at what she actually sends. If she answers your question with a full sentence and adds a detail, she's engaged and just not a frequent texter. If every reply is a single word and she never asks you anything back, that's closer to a signal, and you should weigh it against how she acted on the date. Did she suggest anything about seeing you again, or did you have to bring it up? Did she ask follow up questions in person? Those answers tell you more than reply length does.

Most texts that go nowhere ask for a feeling, like how her week is going or whether she had a good day. Shift the thread toward something concrete instead. Use a place you both mentioned, a plan with a rough time window, or a small question about something she said on the date. Pick one. Keep it simple enough that a short answer still moves things forward. Avoid stacking two questions, since she'll answer the easier one and the other gets dropped. Once she has agreed to something specific, the slow texting matters much less, because the next contact is already on the calendar and the thread has a reason to exist.

Timing depends on the gap. If she replies a day later with a short answer, reply within a few hours, in daylight, and keep yours brief so it doesn't look like you were waiting by the phone. If you sent a plan focused text and got nothing back, wait about two days before a second message. Make that message lighter than the first, and skip anything that asks whether she's still interested. If that also gets nothing, leave the thread alone for a week or so. If she comes back later, pick up with a plan rather than an apology for the silence. If she never responds again, stop. Silence after a good date is still an answer, even if it's not the one you wanted.