The four dates that matter
| Date | When | What it means |
|---|---|---|
| Last spring frost (50%) | May 5 | Half of all years see a freeze after this date. It is an average, not a guarantee. |
| Last spring frost (10%) | May 26 | Only one year in ten freezes after this. Use it for anything you cannot afford to replant. |
| First fall frost (50%) | Oct 15 | Half of all years freeze before this date. Fall crops are counted back from here. |
| First fall frost (10%) | Sep 30 | An early-freeze year. If a crop must finish, aim to harvest before this. |
Spring & summer planting in Sparks
Dates are calculated from this location's own last-frost date, not from a generic zone chart. โBest moon daysโ are the days inside each window that fall in the crop's traditional phase โ the same rule the app uses.
| Crop | Start seed indoors | Plant outdoors | Best moon days | Days to harvest |
|---|---|---|---|---|
| Strawberry (crowns) transplant |
โ | Mar 6 โ Apr 14 | Apr 1 Full Moon |
perennial โ first real harvest next season |
| Garlic cloves/sets Better planted in fall โ see below |
โ | Mar 19 โ Apr 19 | Apr 2โ7 Waning Gibbous |
240โ300 |
| Asparagus (crowns) transplant |
โ | Mar 24 โ Apr 28 | Mar 25, Apr 23 First Quarter |
perennial โ first real harvest 2โ3 years |
| Chives either |
Mar 10 | Mar 24 โ Apr 28 | Mar 24, Apr 18โ22 Waxing Crescent |
75โ90 |
| Onion (from sets/transplants) cloves/sets |
โ | Mar 24 โ Apr 28 | Apr 2โ7 Waning Gibbous |
90โ120 |
| Peas (English/snap) direct sow |
โ | Mar 24 โ Apr 28 | Mar 25, Apr 23 First Quarter |
55โ75 |
| Spinach direct sow |
โ | Mar 24 โ Apr 28 | Mar 24, Apr 18โ22 Waxing Crescent |
35โ50 |
| Cabbage transplant |
Mar 3 | Mar 31 โ Apr 28 | Apr 18โ22 Waxing Crescent |
65โ90 |
| Collards either |
Mar 24 | Mar 31 โ May 19 | Apr 18โ22, May 17 Waxing Crescent |
55โ85 |
| Kale either |
Mar 24 | Mar 31 โ May 5 | Apr 18โ22 Waxing Crescent |
50โ65 |
| Lettuce (leaf) either |
Mar 31 | Mar 31 โ May 26 | Apr 18โ22, May 17 Waxing Crescent |
40โ55 |
| Potato cloves/sets |
โ | Mar 31 โ May 5 | Apr 1, May 1 Full Moon |
70โ120 |
| Radish direct sow |
โ | Mar 31 โ May 26 | Apr 2โ7 Waning Gibbous |
22โ35 |
| Turnip direct sow |
โ | Mar 31 โ May 12 | Apr 2โ7 Waning Gibbous |
40โ60 |
| Broccoli transplant |
Mar 3 | Apr 5 โ May 5 | Apr 18โ22 Waxing Crescent |
55โ80 |
| Brussels Sprouts transplant |
Mar 3 | Apr 5 โ May 5 | Apr 18โ22 Waxing Crescent |
90โ110 |
| Leek transplant |
Feb 24 | Apr 5 โ May 5 | Apr 5โ8, May 2โ3 Waning Gibbous |
100โ120 |
| Lettuce (head) transplant |
Mar 17 | Apr 5 โ May 5 | Apr 18โ22 Waxing Crescent |
60โ85 |
| Parsley either |
Mar 3 | Apr 5 โ May 12 | Apr 18โ22 Waxing Crescent |
70โ90 |
| Parsnip direct sow |
โ | Apr 5 โ May 12 | May 1 Full Moon |
100โ150 |
| Shallot cloves/sets Better planted in fall โ see below |
โ | Apr 5 โ May 5 | Apr 5โ8, May 2โ3 Waning Gibbous |
90โ120 |
| Beet direct sow |
โ | Apr 7 โ May 26 | May 1 Full Moon |
50โ65 |
| Kohlrabi either |
Mar 24 | Apr 7 โ May 12 | Apr 18โ22 Waxing Crescent |
45โ60 |
| Carrot direct sow |
โ | Apr 14 โ May 26 | May 1 Full Moon |
65โ85 |
| Cauliflower transplant |
Mar 3 | Apr 14 โ May 5 | Apr 18โ22 Waxing Crescent |
55โ80 |
| Cilantro direct sow |
โ | Apr 14 โ May 26 | Apr 18โ22, May 17 Waxing Crescent |
45โ70 |
| Swiss Chard direct sow |
โ | Apr 14 โ Jun 4 | Apr 18โ22, May 17 Waxing Crescent |
50โ60 |
| Dill direct sow |
โ | Apr 21 โ Jun 4 | Apr 21โ22, May 17โ20 Waxing Crescent |
40โ60 |
| Cucumber either |
Apr 14 | May 5 โ Jun 4 | May 23 First Quarter |
50โ70 |
| Green Beans (bush) direct sow |
โ | May 5 โ Jun 19 | May 23 First Quarter |
50โ65 |
| Oregano transplant |
Mar 10 | May 5 โ May 26 | May 23 First Quarter |
cut as needed |
| Sage transplant |
Mar 10 | May 5 โ May 26 | May 23 First Quarter |
cut as needed |
| Sweet Corn direct sow |
โ | May 5 โ Jun 19 | May 23 First Quarter |
60โ100 |
| Thyme transplant |
Mar 10 | May 5 โ May 26 | May 23 First Quarter |
cut as needed |
| Zucchini / Summer Squash either |
Apr 14 | May 5 โ Jun 4 | May 23 First Quarter |
45โ60 |
| Basil either |
Mar 24 | May 12 โ Jun 4 | May 17โ22 Waxing Crescent |
30โ60 |
| Dry Beans direct sow |
โ | May 12 โ Jun 9 | May 23 First Quarter |
85โ100 |
| Pole Beans direct sow |
โ | May 12 โ Jun 14 | May 23 First Quarter |
60โ75 |
| Pumpkin direct sow |
Apr 14 | May 12 โ Jun 9 | May 23 First Quarter |
90โ120 |
| Rosemary transplant |
May 5 | May 12 โ Jun 4 | May 23 First Quarter |
cut as needed |
| Tomatillo transplant |
Mar 24 | May 12 โ Jun 4 | May 23 First Quarter |
60โ75 |
| Tomato transplant |
Mar 24 | May 12 โ Jun 4 | May 23 First Quarter |
60โ85 |
| Winter Squash direct sow |
Apr 14 | May 12 โ Jun 9 | May 23 First Quarter |
85โ110 |
| Cantaloupe / Muskmelon either |
Apr 14 | May 19 โ Jun 9 | May 23 First Quarter |
75โ90 |
| Eggplant transplant |
Mar 10 | May 19 โ Jun 9 | May 23 First Quarter |
60โ90 |
| Okra direct sow |
Apr 7 | May 19 โ Jun 14 | May 23 First Quarter |
50โ70 |
| Pepper transplant |
Mar 10 | May 19 โ Jun 9 | May 23 First Quarter |
60โ90 |
| Sweet Potato slips |
โ | May 19 โ Jun 14 | Jun 1โ6 Waning Gibbous |
90โ150 |
| Watermelon either |
Apr 14 | May 19 โ Jun 9 | May 23 First Quarter |
70โ90 |
Fall planting in Sparks
Fall dates count backward from the first frost, and they add time back for the โfall factorโ โ days are shortening and cooling, so a crop grows slower than the seed packet promises. Sowing late is the single most common way a fall garden fails.
| Crop | Sow or set out | Best moon days | Days to harvest | Hardiness |
|---|---|---|---|---|
| Brussels Sprouts | Jun 2 โ Jun 19 | Jun 15โ19 | 90โ110 | hardy |
| Potato | Jun 7 โ Jul 9 | Jun 29 | 70โ120 | semi-hardy |
| Pole Beans | Jun 22 โ Jul 5 | โ | 60โ75 | tender |
| Parsley | Jun 25 โ Jul 9 | โ | 70โ90 | semi-hardy |
| Okra | Jun 27 โ Jul 27 | Jul 21 | 50โ70 | very tender |
| Cabbage | Jul 2 โ Jul 14 | โ | 65โ90 | hardy |
| Carrot | Jul 2 โ Jul 14 | โ | 65โ85 | semi-hardy |
| Collards | Jul 2 โ Jul 24 | Jul 15โ20 | 55โ85 | hardy |
| Cucumber | Jul 2 โ Jul 15 | โ | 50โ70 | tender |
| Broccoli | Jul 7 โ Jul 24 | Jul 15โ20 | 55โ80 | hardy |
| Cauliflower | Jul 7 โ Jul 24 | Jul 15โ20 | 55โ80 | semi-hardy |
| Green Beans (bush) | Jul 7 โ Jul 15 | โ | 50โ65 | tender |
| Lettuce (head) | Jul 7 โ Jul 19 | Jul 15โ19 | 60โ85 | semi-hardy |
| Peas (English/snap) | Jul 7 โ Jul 24 | Jul 21 | 55โ75 | hardy |
| Beet | Jul 12 โ Jul 29 | Jul 29 | 50โ65 | semi-hardy |
| Kale | Jul 12 โ Jul 29 | Jul 15โ20 | 50โ65 | hardy |
| Swiss Chard | Jul 12 โ Jul 29 | Jul 15โ20 | 50โ60 | semi-hardy |
| Zucchini / Summer Squash | Jul 12 โ Jul 20 | โ | 45โ60 | tender |
| Basil | Jul 17 โ Aug 4 | Jul 17โ20 | 30โ60 | very tender |
| Kohlrabi | Jul 17 โ Aug 3 | Jul 17โ20 | 45โ60 | hardy |
| Cilantro | Jul 22 โ Aug 3 | โ | 45โ70 | semi-hardy |
| Lettuce (leaf) | Jul 22 โ Aug 8 | โ | 40โ55 | semi-hardy |
| Turnip | Jul 22 โ Aug 8 | Jul 30โAug 4 | 40โ60 | hardy |
| Spinach | Jul 27 โ Aug 13 | Aug 13 | 35โ50 | hardy |
| Dill | Aug 1 โ Aug 8 | โ | 40โ60 | semi-hardy |
| Radish | Aug 1 โ Aug 26 | Aug 1โ4 | 22โ35 | hardy |
| Garlic | Sep 15 โ Nov 5 | Sep 27โOct 2 | 240โ300 | hardy |
| Shallot | Sep 29 โ Oct 30 | Sep 29โOct 2, Oct 26โ27 | 90โ120 | hardy |
Where these numbers come from
There is no long-record weather station inside Sparks itself, so these frost dates are modelled, not observed. They come from a half-degree climate grid built by fitting the freeze dates of 6,808 NOAA stations (1991โ2020 Normals) against terrain and the USDA 2023 hardiness raster, then reading the cell your city sits in. Checked against the stations themselves, that model lands within about a week on average โ and its zone matches the station's exactly 67% of the time and within one half-zone 97% of the time. A cell covers roughly 35 by 28 miles, so this is a neighborhood answer, not a backyard one. If there is a station-backed location near you, prefer it.
How precise is any of this?
Extension recommendations for the same crop routinely disagree by two to four weeks, and occasionally more, so these offsets should be presented as windows and starting points rather than deadlines. Three things drive the spread. (1) Regional risk tolerance: for warm-season crops, Colorado State and Utah State put tomatoes, peppers and melons out about 14 days after the last frost, while University of Missouri's calendar works out to roughly 25-35 days after the last frost and University of Maryland's window runs from the frost date itself out to 45 days past it. That is a real 6-week spread for the single most popular garden crop, and it exists because a short-season mountain state is optimizing against a short season while a humid continental state is optimizing against cold, wet spring soil. (2) Soil temperature versus calendar date: most Extension services now say the honest trigger is soil temperature at 4 inches, not the frost date, and the frost-relative number is a convenience translation. A cold, wet spring can push the real date two or three weeks past the calendar recommendation. (3) Days-to-maturity is variety-specific and is measured differently for direct-seeded versus transplanted crops - seed catalogs count from transplant date for tomatoes, peppers, eggplant and cole crops, but from sowing for roots and greens - so a 'days to maturity' range of 60-85 for tomato is genuinely 60-85 depending on which packet you bought. Additionally, the average last frost is a 50% probability, meaning half of all years have a frost after that date; Extension services commonly advise waiting 1-2 weeks past it for anything frost-tender, or being prepared to cover. Treat every number here as plus or minus about 10-14 days.
On the station itself: a weather station is one point. Cities hold their heat, valleys pool cold air, and a garden on a north slope can run two weeks behind one a mile away. Treat this page as your starting point and let your own garden correct it โ that is exactly what the journal in the app is for.
Nearby locations
Planting reminders for Sparks
A short note at each new and full moon telling you what is in its window right now for Sparks โ worked out from the frost dates on this page. Free, one click to stop.
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