Introduction

Ragweed allergy tablets (short ragweed sublingual immunotherapy; e.g., RAGWITEK) are most effective when started before pollen appears. The FDA‑approved labeling recommends initiating therapy at least 12 weeks before the expected onset of ragweed pollen season, taking the first dose under medical supervision, and prescribing an epinephrine auto‑injector for home use. This page converts those rules into a practical 2026 “start‑by” calendar for every U.S. state and D.C. so patients and clinicians can align timing with local seasonality.

How to use this calendar

• What “start‑by” means: the latest calendar date in 2026 to begin a ragweed SLIT tablet so that a full ≥12‑week lead‑in is completed before local pollen typically begins.

• Evidence basis: FDA labeling for short ragweed SLIT tablets specifies initiation ≥12 weeks pre‑season and continuation through the season. In‑season initiation has not been established for efficacy.

• Season anchors: In most of the U.S., ragweed season starts in August, peaks around mid‑September, and ends with the first hard frost (6–10 weeks total). We map states to conservative regional onset targets (Aug 1, Aug 10, Aug 15, Aug 20, Aug 25, or Sept 1) and subtract 12 weeks (84 days) to compute “start‑by” dates. Local microclimates vary year to year; confirm with local pollen reporting.

• Internal links for deeper context: see our ragweed overview and treatment options on Ragweed (Allergen Guide) and Pollen Immunotherapy.

Safety and first‑dose requirements (important)

• First dose: Administer in a healthcare setting with 30‑minute observation.

• Epinephrine: Prescribe an auto‑injector and teach proper use; patients should carry it while on therapy.

• Age/eligibility highlights (per label): approved for ages 5–65; contraindicated in severe/uncontrolled asthma and eosinophilic esophagitis; not for immediate symptom relief. Discuss risks, missed‑dose handling, and in‑season initiation limits with your clinician.

Methodology for 2026

We assign each state a conservative “earliest likely onset” anchor and compute the 12‑week lead‑in “start‑by” date for 2026:

• Aug 1 onset → start by May 9, 2026

• Aug 10 onset → start by May 18, 2026

• Aug 15 onset → start by May 23, 2026

• Aug 20 onset → start by May 28, 2026

• Aug 25 onset → start by June 2, 2026

• Sept 1 onset → start by June 9, 2026

These anchors reflect AAFA’s national guidance (weed/ragweed season begins in August, peaks mid‑September), adjusted by latitude/elevation. Always check current‑year local counts before finalizing.

2026 state‑by‑state “start‑by” calendar (ragweed SLIT tablets)

The dates below are conservative targets (earliest likely statewide onset). If your community’s ragweed arrives earlier than typical, advance your start accordingly. For daily verification, use local reporting and our pollen data.

What if you’re starting later than the “start‑by” date?

Labeling notes that the safety and efficacy of initiating ragweed SLIT tablets during the season have not been established. Discuss options with your clinician; many patients focus on symptom control for the current year and then plan to restart with a full ≥12‑week pre‑season lead‑in the following year.

Quick clinical checklist

• Confirm ragweed sensitization (IgE or skin test), age 5–65 years, and no contraindications.

• Schedule a supervised first dose and prescribe/teach epinephrine auto‑injector.

• Begin daily dosing by the “start‑by” date for your state; continue through the season. Track local pollen reports to validate timing and peak.

Related Wyndly resources

• Ragweed (Allergen Guide)

• Pollen immunotherapy: drops/tablets

• Daily pollen data

Educational use only; not a substitute for personalized medical advice. Use FDA labeling and your local allergist’s guidance when prescribing or starting therapy.