Asparagus
Asparagus officinalis
Also known asSparrow grass · Garden asparagus · Espárrago
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 3–8 (winter low around -40°C)
- Frost
- very hardy (survives deep cold)
- Season
- cool (spring/fall)
Growing systems
Root mass: very heavy. Thin-channel systems can't hold this crop.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Soil-based mix (Potting soil) | varies | high | high |
Nutrient demand by stage
NPK ratios are relative weights. EC targets shift through the plant's life.
| Stage | N | P | K | EC (mS/cm) |
|---|---|---|---|---|
| seedling | 2 | 1 | 1 | 1 |
| vegetative | 2 | 1 | 2 | 1.6 |
Aquaponics suitability
Not recommended
Fish waste alone doesn't supply enough of what this crop demands. Grows in hybrid systems with supplemental dosing, but expect active management.
Care notes
Not a typical hydroponic crop, given the perennial habit and the two to three years of establishment before any harvest, though it has been trialled in deep DWC and media beds. Large containers, around 60 L per crown, with deep substrate let the heavy root system develop. Hold EC around 1.4-2.0 mS/cm and pH 6.5-7.5; it takes slightly alkaline conditions. Spear production runs best at 15–25°C, and the crowns need a winter dormancy, freezing or near-freezing for roughly 8 to 12 weeks, to throw good spears in spring. Give full sun, on the order of 20-30 mol/m2/day. Do not cut spears the first two years; let everything grow into fern to build crown reserves. From year three, harvest for two to three weeks, stretching to six to eight weeks by year four. Cut spears at soil level once they reach 15–25 cm, then let the rest grow on as fern, feeding heavily through that phase. In aquaponics, crowns in large media beds beside the fish system can produce for decades; the long establishment is the main hurdle.
Notable varieties
| Cultivar | Type | Origin | Days | Notes |
|---|---|---|---|---|
| Jersey Knight | hybrid | Rutgers University, 1980s | 730 | All-male hybrid. Disease-resistant, productive, the most-recommended commercial variety in the eastern US. Spears thick and uniform. |
| Mary Washington | heirloom | USDA, 1949 | 730 | Open-pollinated mixed-sex heirloom. Less productive than modern all-male hybrids but available as seed (cheaper than crowns), and seed-saving works. The variety to grow if you want to develop your own selections. |
| Purple Passion | open pollinated | 730 | Purple-spear variety, milder flavor, lower fiber (sweet enough to eat raw). Loses purple color when cooked, becomes ordinary green. Decorative. | |
| Jersey Giant | hybrid | Rutgers University | 730 | All-male hybrid, earlier than Jersey Knight. Cold-hardy zone 3. The variety for short-season Northern growers. |