Dimension Granular Pre-Emergent Herbicide - 50 Pound - 50 LB
✅ PROS
- Controls crabgrass AND other grassy weeds for up to 4 months with a single application
- Contains dithiopyr, which provides early post-emergent control on young crabgrass — not just prevention
- 50 lb bag covers 16,000 sq ft at standard rates — enough for 2-3 applications on a typical suburban lawn
❌ CONS
- Must be watered in within 14 days to activate — forgetting this step wastes the entire application
- Not effective on established broadleaf weeds like dandelions or clover — you'll still need a separate herbicide
- Heavy 50 lb bag with no handle makes transport and pouring awkward for older users
The Verdict
Dimension Granular Pre-Emergent Herbicide Review: The 50 LB Bag That Actually Pays Off
If you’ve waged war on crabgrass and lost, the problem might not be your tactics — it’s your timing. Pre-emergent herbicides are the only real defense against crabgrass, and Dimension Granular Pre-Emergent is one of the most effective weapons you can spread. But at 50 pounds, this isn’t a casual purchase. Here’s what you need to know before you commit.
What’s In the Bag
You’re getting 50 pounds of granular herbicide with 0.15% dithiopyr as the active ingredient. That’s the key differentiator here. Most pre-emergents (like prodiamine-based products) only prevent germination. Dithiopyr does that plus provides early post-emergent control — meaning if you’re slightly late and crabgrass has already sprouted, Dimension can still knock it out as long as the weeds are young.
The bag covers roughly 16,000 square feet at the standard 3.1 lb per 1,000 sq ft rate. If you’re treating a typical quarter-acre lot (about 10,000 sq ft of turf), you’ll get one full application plus a second application for late summer — or you can split it into spring and fall treatments.
Real-World Performance
Applied correctly, Dimension delivers. The granular formulation spreads evenly through a broadcast spreader, and the product’s ability to form a barrier in the soil is genuinely reliable. Most users report 90%+ crabgrass prevention when applied before soil temperatures hit 55°F.
The 4-month residual control is accurate, not marketing fluff. One spring application typically carries you through the entire crabgrass germination window, which is the longest of any pre-emergent on the market. You’ll also get suppression of foxtail, barnyardgrass, and other grassy weeds.
What Buyers Praise
The 4.7-star rating (235 reviews) reflects consistent satisfaction. One reviewer noted: “I’ve tried every crabgrass preventer on the shelf. This is the first one that actually kept my lawn clean all summer.” Another long-time user mentioned the cost efficiency: “This bag lasted me two seasons. The per-application cost is half of what I was paying for the Scott’s stuff.”
The early post-emergent capability gets frequent shoutouts. Multiple reviewers describe catching crabgrass sprouts in late spring, applying Dimension, and seeing them die off within two weeks.
Where It Falls Short
The watering requirement is non-negotiable. Dimension needs 0.5 inches of irrigation within 14 days of application to activate. Skip this, and you’ve wasted 50 pounds of product and a season of protection. If you don’t have reliable irrigation or consistent spring rainfall, this is a real risk.
Broadleaf weeds are unaffected. Dandelions, clover, plantain — Dimension won’t touch them. You’ll need a separate broadleaf herbicide like 2,4-D or a combination product for those.
Physical handling is a chore. The 50 lb bag has no handle, and the granule consistency makes it prone to clumping if stored in humid conditions. Pouring into a spreader requires two hands and some care.
Who Should Buy This
- Lawn care enthusiasts with 5,000-20,000 sq ft of turf who want professional-grade results
- Crabgrass veterans who’ve dealt with breakthrough infestations from weaker products
- Cost-conscious homeowners willing to invest upfront for 2+ seasons of protection
Skip it if you have a postage-stamp lawn under 3,000 sq ft (you’ll waste most of the bag), lack any irrigation system, or want a single product to handle all weed types.
FAQ
When should I apply Dimension? Apply when soil temperatures reach 55°F consistently — typically 2-4 weeks before your area’s last frost date. For most of the Midwest and Mid-Atlantic, that’s mid-April. Southern lawns may need application in February-March.
Can I overseed after using Dimension? No. Pre-emergents don’t discriminate — they’ll prevent grass seed germination too. Wait 8-12 weeks after application before overseeding, or 2-3 weeks after a fall application.
How do I know if it’s working? You won’t see it working — that’s the point. If you have zero crabgrass by July, it worked. If you see breakthrough, you either applied too late, didn’t water it in, or had heavy rain that washed it away.
The Verdict
Buy it if: You’re serious about a crabgrass-free lawn and can commit to the watering requirement. The dithiopyr chemistry, extended residual control, and cost-per-application value make this one of the smartest purchases in lawn care.
Skip it if: You have a small lawn, no irrigation, or want a one-product-fixes-everything solution. This is a specialized tool for a specific job — but it does that job exceptionally well.
Rating: 4.6/5 — Deducting half a star for the fussy activation requirement and the physical awkwardness of the bag. But for crabgrass control, this is the gold standard.
Where to Buy
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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.